E>  a  A  FLY  . 

0  F  TH  E 

UNIVLR/S^fY 
OF    ILLINOIS 

630.7 


rvo.49-60 


AGRICULTURE 


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L16I— O-1096 


UNIVERSITY  OF  ILLINOIS 

Agricultural  Experiment  Station. 


URBANA,  MARCH,    1900 


BULLETIN    No.    57. 


THE  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 

The  following  pages  are  the  result  of  studies  made  by  the  writer 
during  the  past  five  years  to  ascertain  the  kinds  of  smuts  infesting  our 
cultivated  plants,  the  injuries  inflicted  by  them,  facts  in  their  life  his- 
tories, and  the  most  practical  methods  of  preventing  their  ravages. 
Some  of  the  smuts  have  been  more  thoroughly  studied  than  others 
because  of  opportunities  offered,  and  the  above  points  of  investigation 
also  have  varied  considerably  in  the  study  of  the  different  species. 

GENERAL  NATURE  OF  SMUTS. 

General  Structure.  For  the  information  of  those  who  are  unac- 
quainted with  smuts,  except  in  a  very  general  way,  it  may  be  said  that 
they  are  parasitic  plants  belonging  to  the  group  known  as  fungi.  They 
can  usually  be  easily  told  by  the  dusty  outbreaks  that  they  produce  on 
certain  parts  of  their  hosts — the  plants  they  attack — when  they  reach 
their  reproductive  stage.  Examples  familiar  to  everyone  are  such 
formations  on  corn  and  oats,  known  as  corn  smut  and  oat  smut. 

As  with  other  fungi  a  smut  fungus  consists  of  two  stages — the 
growth,  or  mycelial  stage,  and  the  reproductive,  or  spore  stage.  The 
former  has  to  do  with  spreading  the  fungus  through  its  host  and  gather- 
ing food  for  its  development  from  the  tissue  through  which  it  passes. 
The  mycelium  [Plate  U]  consists  of  hyaline  branched  threads,  at  first 
filled  with  protoplasmic  contents,  but  with  age  losing  this  and  becoming 
septate,  that  push  their  way  between  and  into  the  cells  of  the  host. 
Being  within  the  plant,  this  stage  is  invisible  to  the  naked  eye,  and  there 
is  usually  nothing  peculiar  in  the  way  of  discolored  or  swollen  tissue  to 
separate  such  an  infested  plant  from  one  free  from  the  fungus. 


290  BULLETIN  NO.   57.  [March, 

The  spore  stage,  however,  [Plates  A-Q]  produced  by  large  num- 
bers of  modified  threads  of  the  mycelium,  being  formed  near  the  surface 
of  some  part  of  the  plant,  usually  becomes  visible  from  the  first  by  the 
distortion  thus  produced  and  by  the  prevention  of  the  normal  growth 
of  plant  tissues  or  organs.  These  outbreaks  mature  into  a  dark,  dusty 
mass  of  spores  [Plate  R,  1-6]  which,  in  the  forms  we  have  to  consider, 
are  microscopic,  roundish,  single  cell  bodies  that  consist  of  a  more  or 
less  thickened,  and  very  often  spiny  wall  enclosing  protoplasmic  con- 
tents. The  wall  is  more  or  less  tinted  and  thus  gives  the  dark  color 
to  the  spores  in  mass. 

The  life  cycle  of  the  smut  is  something  as  follows:  The  spores 
germinate  [Plates  S-T]  by  sending  out  a  slender  hyaline  germ  thread,  or 
pro-mycelium,  which  either  has  the  power  of  penetrating  by  very  narrow 
infection  threads  directly  into  the  young,  tender  tissue  of  its  host  and 
there  giving  rise  to  the  mycelium,  or  else  this  germ  tube  remains  short 
and  at  the  septa  on  its  sides  or  on  its  end  gives  rise  to  slender,  short, 
colorless  bodies,  called  sporidia,  which  under  certain  conditions  of 
moisture  and  nourishment  reproduce  themselves  in  countless  numbers 
by  budding  at  their  ends.  In  this  way  the  number  of  germs  is  greatly 
increased  and  the  chance  of  infecting  the  host  likewise  strengthened, 
since  these  sporidia  in  ordinary  water  may  give  rise  by  germination  to 
slender  infection  threads  whose  office  is  the  same  as  those  originating 
from  the  germ-tube  of  the  spore. 

The  smut  germs  can  infect  only  their  host  plants,  and  these  only 
when  the  exposed  parts  are  quite  young  and  usually  only  at  certain  par- 
ticular places.  Most  frequently  it  is  through  the  very  young  parts  of 
the  germinating  seed  that  the  fungus  makes  its  entrance  into  its  host, 
and  then  by  the  growth  of  its  mycelium  follows  the  upward  growth  of 
the  plant,  becoming  visible  finally  through  the  formation  of  its  spores, 
which  in  such  cases  are  generally  produced  in%  those  parts  that  would 
have  given  rise  to  the  flowers. 

Kinds.  Such  in  general  is  the  life  history  of  these  parasites.  There 
have  been  found  in  Illinois  about  fifty  different  kinds  occurring  on  some 
seventy-five  different  hosts.  The  forms  considered  in  this  paper  are  of 
especial  interest  because  the  hosts  they  inhabit  are  of  economic  im- 
portance. 

Perhaps  the  most  important  ones  are  those  that  appear  in  the 
panicles  of  oats,  known  as  loose  and  hidden  smuts  of  oats, — so  called 
because  the  former  entirely,  while  the  latter  only  partially,  destroys  the 
flower  parts,  the  outer  glumes  at  least  in  the  latter  case  remaining  more 
or  less  intact.  Tall  oat  grass  is  also  the  host  of  a  form  similar  in  appear- 
ance to  the  hidden  smut  of  oats,  while  loose  smut  of  wheat  is  very  much 
like  that  of  the  loose  oat  smut.  Besides  the  loose  smut,  wheat  is  the 
host  here  of  at  least  one,  and,  perhaps,  both  of  the  stinking  smuts — 


IQOO.~\  SMUTS    OF    ILLINOIS5    AGRICULTURAL    PLANTS.  291 

forms  which  occur  in  the  grain  without  affecting  the  surrounding  glumes, 
hence  very  easily  overlooked.  Corn  smut,  next  to  oat  smut,  is  our 
most  common  species  and  is  also  the  most  conspicuous  form,  breaking 
out  on  almost  any  part  of  its  host.  This  same  smut  also  has  been  found 
at  the  Experiment  Station  on  teosinte,  a  plant  not  ordinarily  cultivated 
so  far  north.  Barley  is  not  now  extensively  raised  in  this  state,  and 
consequently  the  loose  and  covered  smuts  which  destroy  its  spikes  are 
not  so  common  or  important  as  they  would  be  otherwise.  The  smut 
which  destroys  the  seed  of  sorghum  and  broom-corn,  known  as  grain 
smut,  is  sometimes  a  quite  common  and  injurious  foe  of  these  plants 
though  they  are  not  widely  cultivated.  Head  smut  of  sorghum,  which 
differs  greatly  from  the  grain  smut  of  the  same  host  by  changing  the 
whole  panicle  into  a  large  smutty  mass,  has  been  found  here  but  once. 
The  smut  of  grasses,  which  breaks  out  in  rather  inconspicuous  dusty 
lines  on  the  leaves,  has  for  its  hosts  of  economic  importance  timothy, 
redtop,  and  blue-grass,  and  is  not  uncommon,  and  occasionally  is  a 
quite  injurious  fungus.  The  smut  which  occurs  in  the  spikes  of  Hun- 
garian grass  has  been  collected  but  once,  and  then  in  southern  Illinois. 

Damage  done.  The  financial  loss  caused  by  any  fungus  depends 
upon  several  things,  as  follows:  the  value  of  the  host  as  an  economic 
plant,  the  part  of  the  host  most  directly  injured,  the  severity  of  the 
attack,  and  the  frequency  of  occurrence.  From  a  consideration  of  these 
points,  if  he  has  accurate  data,  one  can  get  a  fairly  good  idea  of  the  loss 
caused  by  any  fungus. 

From  the  fact  that  the  smuts  very  often  destroy  entirely  the  part  of 
the  plant  for  which  it  is  raised,  it  is  easier  to  make  an  estimate  of  the 
damage  caused  by  them  than  in  the  case  of  most  other  fungi.  For  in- 
stance, if  one  finds  that  ten  out  of  every  hundred  of  his  oat  panicles 
are  smuttled,  he  can  make  an  estimate  of  10  per  cent,  damage.  It  may 
be  even  more  than  this,  for  we  know  that  in  some  plants  the  smut  may 
gain  entrance  into  the  stalks  but  not  succeed  in  producing  its  spores 
because  of  the  too  rapid  growth  or  maturing  of  plant  tissues.  In  this 
case  the  fungus  presumably  has  an  effect  in  reducing  the  quality  and 
yield  of  seed,  though  it  is  not  very  likely  that  many  plants  are  so  in- 
fected or  influenced  enough  to  have  a  very  appreciable  effect. 

A  good  many  estimates  have  been  made  for  various  states  and  the 
country  at  large  of  the  damage  caused  by  different  smuts,  and  these 
usually  show  the  loss  to  be  very  considerable.  In  fact  the  smuts  cause 
a  greater  loss  among  our  strictly  agricultural  plants  than  any  other 
fungi,  unless  it  be  the  rusts.  There  is  reason  to  suppose,  however,  that 
while  these  estimates  may  not  in  many  cases  be  exaggerated,  still  they 
have  been  chiefly  in  the  nature  of  guesses  made  for  large  areas  based 
upon  limited  observation  in  some  restricted  area.  Examinations  made 
in  various  parts  of  this  state  have  shown  that  while  one  can  determine 


292  BULLETIN    NO.     57.  \_Marcll, 

quite  accurately  the  loss  caused  by  oat  smut  in  any  field,  by  making 
counts  of  several  hundred  heads  in  each  of  three  or  four  places  in  it. 
still  conclusions  are  not  to  be  drawn  from  that  field  as  to  the  amount  of 
smut  in  other  fields  in  the  neighborhood.  Neither,  if  he  has  gone  over 
the  fields  of  the  neighborhood,  is  he  justified  in  drawing  conclusions 
from  this  as  to  the  amount  of  smut  in  the  rest  of  the  state,  at  least  not 
without  some  general  inspection  of  it. 

Of  all  the  smuts  in  this  state  those  of  oats  undoubtedly  cause  the 
greatest  loss  year  after  year.  This  is  due  to  the  facts  that  oats  are  very 
extensively  raised,  that  the  smut  is  found  more  or  less  abundant  in  all 
the -fields  (sometimes  destroying  as  high  as  twenty  to  forty  per  cent.  ), 
and  that  the  grain  is  directly  and  entirely  destroyed.  If  wheat  had  not 
been  disappearing  somewhat  from  culture,  it  is  very  likely  that  the 
loose  smut  of  this  plant  would  cause  a  greater  loss  than  the  oat  smuts, 
because, while  it  does  not  generally  give  so  high  a  per  cent,  of  smut, the 
value  of  the  crop  would  more  than  offset  this.  Stinking  smut  of  wheat 
in  some  localities  or  fields  does  considerable  damage,  but  it  has  not  such 
a  universal  occurrence  as  the  loose  smut.  The  smut  on  corn  is  one  of  the 
most  common  of  these  pests,  but  the  loss  caused  by  it  is  usually  indi- 
rect; that  is,  the  smut  commonly  breaks  out  on  other  parts  of  the  plant 
than  the  ears  and  in  such  cases  affects  them  only  by  using  food  that 
might  go  for  their  growth.  The  loss,  however,  is  always  something  and 
in  some  fields  undoubtedly  becomes  quite  considerable,  though  it  is 
doubtful  if  it  causes  as  much  damage  as  is  generally  supposed.  The  loss 
caused  by  the  other  smuts  is  more  insignificant,  due  in  part  to  the  more 
restricted  cultivation  of  the  hosts  and  in  part  to  a  greater  variability  in 
the  presence  of  the  smuts  that  attack  them.  In  occasional  fields,  how- 
ever, they  sometimes  do  much  mischief. 

PREVENTION  OF  SMUTS. 

Theory.  The  fact  that  smuts  cause  so  great  a  loss  to  certain  of  our 
agricultural  plants  early  led  to  experiments  to  prevent  their  ravages. 
These  attempts  while  mostly  crude  and  ineffectual  were  still  along  the 
right  line,  in  that  they  dealt  with  treatment  of  the  seed.  Smuts,  with  a 
few  exceptions,  unlike  most  other  fungi,  do  not  spread  the  disease  from 
one  plant  to  another.  They  are  also  more  restricted  as  to  the  time  and 
place  of  entrance  to  their  hosts.  With  most  of  those  of  economic  im- 
portance, corn  smut  being  the  prominent  exception,  infection  is  success- 
ful only  when  the  germ  threads  can  penetrate  the  very  young  tissue  of 
the  germinating  seed.  This  being  the  case  there  is  but  a  very  short 
time,  while  the  plant  is  still  underground,  that  there  is  danger  from  the 
smut  germs. 

With  most  of  the  smuts  the  germs  are  not  so  generally  distributed 
in  the  ground  as  to  be  a  source  of  infection.      It  has  been  found  that  it 


/poo.]  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  293 

is  those  which  adhere  to  the  seed  that  are  dangerous.  These  spores  were 
blown  on  the  seed  in  the  field;  or,  in  cases  where  there  were  smutty 
kernels,  these  became  ruptured  with  the  handling  of  the  grain  and  thus 
distributed  their  spores  to  the  seed.  From  these  considerations  it  will 
be  seen  that  the  proper  way  to  prevent  the  appearance  of  smut  in  a  crop 
is  to  use  seed  that  is  free  from  living  smut  germs. 

Use  of  clean  Seed.  One  way  to  prevent  smut  would  undoubtedly  be 
the  use  of  seed  entirely  free  from  germs.  This  is  best  accomplished  by 
obtaining  seed  from  fields  that  have  had  no  smut  in  them,  though  it  is 
much  more  difficult  to  do  this  with  some  crops  than  with  others.  If 
more  attention,  however,  were  paid  to  the  source  of  seed,  the  losses 
caused  by  these  fungi  would  be  greatly  diminished.  One  must  not  judge 
of  the  cleanliness  of  seed  by  a  mere  examination  of  it;  since,  except 
in  those  cases  where  the  smut  is  present  in  smutty  kernels,  this  would 
not  show  whether  any  germs  were  present  or  not.  It  takes  a  thorough 
knowledge  of  the  field  from  which  the  grain  came,  and  in  some  cases 
possibly  its  after  handling,  to  determine  the  condition  of  the  seed  in 
this  respect. 

With  such  crops  as  oats,  even  when  a  person  has  used  ordinary  care 
in  the  selection  of  his  seed,  he  may  get  varying  results  with  different 
seasons.  In  most  fields  there  is  at  least  a  little  smut  present,  and  the 
conditions  of  moisture,  etc.,  especially  at  the  time  of  planting,  have 
much  to  do  with  determining  whether  this  shall  become  greater  in  the 
succeeding  crop.  So  it  may  happen  that  a  farmer  who  one  year  has 
used  care  in  the  selection  of  seed  gets  a  smuttier  crop  than  he  did  some 
other  year  when  he  had  not  used  this  care.  From  such  experience  some 
farmers  judge  that  season  is  the  one  influence  that  regulates  the  amount 
of  smut.  It  is  an  important  factor,  but  the  most  important  factor  is  the 
degree  of  freedom  of  seed  from  germs. 

The  effect  of  neglect  in  selecting  seed  was  shown  in  the  investiga- 
tions of  amount  of  smut  in  this  state.  From  complaints  it  was  found  on 
examination  that  the  farmers  of  southern  Illinois  suffered  much  more 
from  oat  smut  than  those  of  central  Illinois.  In  the  former  region  much 
less  attention  had  been  paid  to  the  seed  used.  That  greater  care  in  this 
direction  would  have  been  helpful  was  shown  in  the  cases  of  a  few  per- 
sons who  watched  the  condition  of  their  oats. 

Use  of  chemically  treated  Seed.  Another  way  to  prevent  smut  is  to 
kill  all  of  the  germs  that  are  attached  to  the  seed.  Experiments  in  soak- 
ing the  seed  with  chemicals  of  various  kinds  have  been  tried  for  years 
in  Europe  and  more  recently  in  this  country.  Among  the  earlier  things 
used  were  brine,  lye,  and  copper  sulfate.  Most  of  the  treatments  seem 
to  have  been  for  the  prevention  of  the  stinking  smut  of  wheat.  With 
the  exception  of  copper  sulfate  these  earlier  remedies  have  given  little 
satisfaction,  and,  even  with  this,  although  to-day  it  is  perhaps  more 


294  BULLETIN  NO.    57.  \_March, 

generally  used  over  the  world  than  any  other  treatment,  there  is  con- 
siderable danger  of  injuring  the  seed  when  it  is  made  severe  enough  to 
be  quite  efficient. 

With  the  advent  of  experiment  stations,  more  careful  experimenta- 
tion with  a  great  variety  of  chemicals  was  conducted.  From  among 
the  many  tried  there  have  been  discovered  several  that  give  rather  satis- 
factory results.  New  methods  of  treating  the  seed  have  also  been  de- 
veloped. Formerly  the  seed  was  allowed  to  soak  from  one  to  twenty- 
four  hours  according  to  the  strength  of  the  solution.  Now  sprinkling 
the  solutions  over  the  grain,  stirring  the  latter  to  wet  it  uniformly,  seems 
to  give  as  good  results,  while  the  work  is  much  quicker  and  less  cum- 
bersome and  the  grain  more  easily  dried.  Of  all  the  chemical  solutions 
that  have  been  tried,  corrosive  sublimate,  potassium  sulfid,  Ceres  pulver 
(apparently  composed  chiefly  of  potassium  sulfid),  copper  sulfate,  lysol, 
and  formalin  have  given  the  best  results. 

Formalin  which,  without  doubt,  heads  this  list,  is  a  commercial 
name  for  a  forty  per  cent,  solution  of  formaldehyde.  While  not  poison- 
ous it  has  a  very  pungent  and  penetrating  odor,  making  it  one  of  the 
best  disinfectants.  With  seed  treatment  for  smuts,  it  is  used  at  the  rate 
of  one  'pound  of  the  liquid  to  forty  or  fifty  gallons  of  water.  It  is 
sprinkled  on  the  grain,  while  the  latter  is  thoroughly  stirred,  at  the  rate 
of  one  to  two  gallons  a  bushel.  After  treatment  the  grain  is  left  in  sacks 
for  a  few  hours  and  then  planted.  The  simplicity  of  this  treatment, 
with  possibilities  of  its  further  improvement,  will  undoubtedly  make  it 
more  popular  than  the  following  very  effective  though  somewhat  cum- 
bersome method. 

Use  of  hot  Water  treated  Seed.  Jensen,  of  Denmark,  was  the 
first  person  to  bring  into  prominence  the  use  of  hot  water  as  a  seed  treat- 
ment. The  Kansas  Experiment  Station  in  this  country,  stimulated  by 
these  results,  also  made  numerous  experiments  with  it  for  smuts  of  oats 
and  wheat,  and  since  then  other  stations  have  contributed  experiments, 
so  that  the  literature  on  this  method  of  treatment  is  perhaps  more  ex- 
tensive than  that  of  all  the  other  treatments  combined.  Hot  water 
treatment  of  seed  is  without  doubt  the  most  generally  effective  treatment 
that  has  been  discovered.  The  objections  against  it  are  its  cumbersome- 
ness,  the  work  required  to  treat  large  amounts  of  seed,  and  the  difficulty 
in  drying  the  seed  after  treatment.  These  are  objections  that  hold  least 
with  the  formalin  treatment  just  described,  though  even  with  this,  as 
now  conducted,  the  wetness  of  the  seed  is  objectionable. 

This  treatment  consists  in  the  immersion  of  seed  in  hot  water,  the 
time  of  immersion  and  temperature  of  the  water  varying  with  the  seed 
to  be  treated.  In  general  the  immersion  varies  from  five  to  fifteen  min- 
utes and  the  temperature  (inversely  to  the  time)  from  130°  to  i45°F. 
It  is  best  not  to  treat  over  a  bushel  at  a  time,  in  order  that  all  of  the 


J9OO.~]  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  295 

grain  may  receive  equal  exposure  to  the  heat.  It  has  been  found  de- 
sirable to  have  two  barrels  of  hot  water,  one  at  the  required  temperature 
and  the  other  a  little  below  it,  so  that  the.  seed  being  placed  in  the  latter 
barrel  first  has  its  temperature  raised  enough  to  prevent  it  lowering  that 
of  the  second,  which  must  be  kept  at  the  required  degree.  A  coarse 
gunny-sack  to  hold  the  seed,  with  plenty  of  room  for  circulation  of 
the  water,  a  cross-bar  and  a  lever  to  lift  the  sack  in  and  out  of  the 
barrels,  means  for  heating  plenty  of  .water,  and  a  trustworthy  thermom- 
eter are  essentials  for  this  treatment. 

One  man  is  needed  to  keep  track  of  the  time  of  immersion  and 
temperature  of  water,  and  another  to  dip  the  seed.  When  placed  in 
either  barrel  the  sack  should  be  raised  clear  of  the  water  several  times 
to  allow  it  to  drain  off  or  else  the  temperature  of  the  seed  will  never 
come  up  to  that  of  the  water.  A  minute  or  two  is  all  that  is  necessary 
for  treatment  in  the  first  barrel  and  then  the  sack  is  quickly  transferred 
to  the  second  and  after  several  dippings  kept  entirely  immersed  for  the 
remainder  of  the  required  time.  After  treatment  the  seed  is  imme- 
diately spread  out  to  cool  and  if  not  planted  soon  must  be  turned  over 
every  day  until  thoroughly  dry. 

It  seems  desirable  to  treat  seed  about  the  time  it  is  to  be  planted, 
for  otherwise  it  takes  considerable  space  and  care  to  dry  thoroughly  any 
quantity  and  there  is  danger  of  its  germinating  somewhat  before  this  is 
accomplished.  If  sown  broadcast  by  hand  it  can  just  as  well  be  sown  as 
soon  as  treated,  but  if  planted  by  drill  it  should  be  dried  somewhat  and 
even  then  it  will  not  feed  well,  unless  a  force  drill  is  used.  In  either 
case  the  swollen  condition  of  the  grain  should  be  taken  into  considera- 
tion and  allowance  made  for  the  desired  rate  per  acre.  Generally  hot- 
water  treated  seed  germinates  quicker  and  obtains  an  earlier  start  than 
untreated  seed. 

For  the  benefit  of  those  who  may  wish  to  use  any  of  these  seed 
treatments,  there  is  given  in  Table  i  general  directions  for  the  most 
successful  methods  with  the  various  smuts  of  our  cereals.  The  direc- 
tions printed  in  italics  are  those  recommended,  having  been  found  most 
efficient  in  our  experimental  work. 


296 


BULLETIN    N'O.     57. 


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/poo.]  SMI TS  OK  ILLINOIS'  AGRICULTURAL  PLANTS.  297 

LOOSE  AND   HIDDEN   SMUTS  OF  OATS. 
Ustilago  Avena  ( Pers.  )  Jens.      Ustilago  levis  (Kell.  &  Sw. )  Magn. 

Life  History.  There  are  two  distinct  smuts*  of  oats.  In  the  loose 
smut  the  infected  flowers  of  the  panicle  are  entirely  destroyed  by  the 
spore  formation,  and  each  is  changed  into  a  dusty  olive  brown  mass 
that  after  maturity  is  gradually  disseminated,  eventually  leaving  behind 
only  the  naked  branches  of  the  panicle.  With  the  covered  smut  the 
destruction  of  the  flower  parts  is  much  less  complete,  the  spore  mass  is 
less  dusty  and  more  of  a  blackish  brown.  In  this  form  the  smut  usually 
shows  through  the  thin  covering  membrane  at  base  of  the  flower,  the 
upper  part  of  the  glumes  remaining  intact.  More  rarely  the  glumes 
show  no  sign  of  the  smut  which  is  limited  to  the  parts  within,  and  even 
sometimes  the  hard  flowering  glume  and  palet  are  normally  developed 
as  if  enclosing  a  sound  seed,  and  the  presence  of  the  fungus  is  deter- 
mined only  by  tearing  these  apart.  These  enveloping  parts  furnish  such 
protection  against  dissemination  of  the  spores  that  frequently  the 
smutted  flowers  may  be  found  in  badly  smutted  grain  after  it  is  threshed. 
In  one  instance  only  was  the  smut  found  developing  in  any  other  part 
of  the  plant,  the  exception  being  in  an  upper  leaf  where  it  broke  out 
in  rather  inconspicuous  lines.  In  both  species  there  are  occasionally 
found  panicles  in  which  the  lower  flowers  only  are  smutted,  and  all  or 
a  part  only  of  the  culms  from  a  stool  may  show  the  presence  of  the 
fungus.  Besides  destroying  the  grain  these  smuts  more  or  less  stunt 
the  growth  of  the  culms  so  that  they  average  several  inches  shorter  than 
the  free. 

The  spores  of  the  two  species  also  present  but  small  differences* 
Those  of  Ustilago  Avence  are  minutely  echinulate,  lighter  colored  on 
one  side,  and  vary  chiefly  from  elliptical  to  spherical  (usually  sub- 
spherical)  in  shape  and  from  6-9?/t  in  diameter.  With  Ustilago  levis 
the  difference  consists  in  a  smooth  membrane,  with  perhaps  spores 
somewhat  darker  in  color  and  more  uniform  in  shape  and  size.  Both 
germinate  readily  in  water,  though  the  hidden  smut  apparently  the  more 
abundantly.  A  three-  or  four-celled  pro-mycelium  is  produced  from  the 
lighter  side  of  the  spore  and  this  gives  rise  to  a  few  sporidia  at  the 

*For  a  long  time  the  writer  considered  that  Ustilago  Aventc  var.  levis  Kell.  & 
Sw.  (later  raised  to  specific  rank  by  Magnus  as  Ustilago  levis]  was  only  Ustilago 
Aveme  in  which  the  fungus  had  been  tardy  in  gaining  entrance  into  the  floral  parts 
and  so  being  only  partially  effective  in  destroying  them.  Lately,  however,  going 
carefully  over  all  the  herbarium  collections  and  taking  into  consideration  field  obser- 
vations, it  seems  more  probable  that  this  host  really  has  two  distinct  species.  Our 
experiments  were  made  under  the  former  impression  and  so  no  special  attention  was 
paid  at  the  time  to  the  character  of  the  infested  panicles.  It  is  undoubtedly  true, 
however,  that  with  our  prevention  and  infection  experiments  we  were  working  largely, 
if  not  entirely,  with  the  covered  smut,  Ustilago  levis. 

|A  u  is  one  twenty-five  thousandth  of  an  inch. 


298  BULLETIN  NO.   57.  [March, 

sides  or  apex,  or  often  to  germ  threads  either  by  prolongation  of  the 
pro-mycelium  or  by  development  of  basal  branches.  These  probably 
act  as  infection  threads.  Knee  joints,  formed  by  bending  of  the  thread 
closely  on  itself  or  by  lateral  outgrowths  around  the  septum,  also  occur. 
The  sporidia  develop  infection  threads.  The  pro-mycelium  sometimes 
becomes  abstricted  near  the  base  and  falls  off,  continuing  its  develop- 
ment alone.  In  nutrient  solutions  the  germination  is  more  vigorous, 
though  not  always  more  abundant,  and  the  sporidia  are  much  more 
common,  because  of  their  reproduction  by  budding,  until  exhaustion  of 
nutrient,  when  they  may  produce  infection  threads. 

It  has  been  proved  by  seed  treatment  that  infection  takes  place 
from  the  spores  attached  to  the  seed.  Our  experiments*  with  covered 
smut  also  show,  as  claimed  by  Jensen,  that  it  is  those  spores  which  in 
the  field  have  succeeded  in  falling  down  between  the  flowering  glumes 
while  open  during  shedding  of  pollen  that  are  most  responsible.  The 
glumes  are  thus  a  great  means  of  protection  after  they  have  once  closed 
around  the  seed.  Infection  takes  place  by  the  penetration  of  the  infec- 
tion threads  of  the  pro-mycelia  or  of  the  sporidia  into  the  very  young 
tissue  of  the  germ,  usually  before  or  soon  after  protruding  from  the 
enveloping  glumes.  Once  having  gained  entrance  the  fungous  threads 
must  succeed  in  reaching  the  young  tissue  just  beneath  the  growing 
point,  after  which  they  follow  the  upward  growth  during  the  several 
weeks  necessary  for  the  development  of  the  oats,  showing  no  external 
sign  of  the  smut's  presence  until  the  protruding  of  the  panicle.  When 
the  flower  parts  are  being  differentiated  the  fungus  for  the  first  time 
seems  to  gain  supremacy  and  its  reproductive  stage  is  now  developed 
to  the  destruction  or  prevention  of  these  parts,  so  that  by  the  time  the 
panicles  appear  the  spores  are  mostly  developed. 

Damage.  As  has  been  pointed  out  the  oat  smuts  by  producing 
their  spores  in  the  panicles  prevent  seed  formation,  and  usually  destroy 
all  of  the  grain  of  such  a  panicle.  The  loss,  then,  is  easy  of  estimation 
after  one  has  determined  the  per  cent,  of  smutty  panicles  in  a  field.  In 
order  to  get  as  accurate  an  idea  as  possible  of  the  damage  caused  by 
these  smuts,  since  they  inflict  a  greater  loss  than  any  of  the  others,  a 
large  number  of  determinations  of  the  per  cent,  of  smut  in  oat  fields 
has  been  made.  The  data  thus  obtained  are  given  in  Table  2.  Most 
of  these  determinations  were  made  in  Champaign  county  and  on  two 
bicycle  trips  taken  in  1897-8  through  central  and  southern  Illinois.  In 
these  cases  nearly  every  field  seen  along  the  road  was  entered  and  a  de- 
termination made.  A  few  counts  were  made  by  persons  interested  in 
various  parts  of  the  state,  and  the  numbers  163-195  are  total  counts  of 

*Smut  mixed  dry  with  oats  gave  only  2%  smutted  plants,  that  mixed  wet  gave 
9%,  while  hulled  seed  mixed  wet  gave  TL%.     See  Table  7. 


igoo.~\  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  299 

small  plats  raised  at  the  Experiment  Station  from  seed  obtained  from 
thirty-four  localities  scattered  over  the  state.  It  was  found  that  a  quite 
accurate  determination  could  be  made  by  counting  from  five  hundred 
to  a  thousand  panicles  in  each  of  three  or  four  places  scattered  over 
the  field,  noting  the  number  of  smutty  panicles  in  the  total  counts. 
From  these  observations  and  from  correspondence  carried  on  concern- 
ing this  subject,  the  following  conclusions  are  made. 

Taking  the  state  as  a  whole  the  damage  done  varies  with  different 
years,  in  some  being  quite  considerable  and  in  others  rather  inconspic- 
uous. The  years  1895-7  were  ones  in  which  the  loss  was  considerably 
higher  than  in  1898-9,  perhaps  the  greatest  extremes  being  presented 
by  the  years  1896  and  18.98.  This  variation  is  probably  largely  due  to 
seasonal  variations. 

There  is  a  difference  in  different  parts  of  the  state  as  to  the  com- 
parative loss  from  this  fungus.  For  instance,  the  hard  pan  region  of 
southern  Illinois,  the  northern  boundary  of  which  is  somewhere  near 
the  regions  of  Pana  and  Mattoon,  undoubtedly  has  suffered  more  in  this 
respect  than  the  more  fertile  part  of  central  Illinois,  of  which  Cham- 
paign county  may  be  taken  as  a  type.  This  was  plainly  brought  out  by 
correspondence  and  by  the  observations  made  on  the  bicycle  trip  in 
1897  which  covered  a  considerable  territory  in  both  of  these  regions, 
the  general  average  of  counts  made  showing  n%  of  smut  in  one  case 
and  3%  in  the  other.  This  difference  is  attributable  to  the  difference 
in  seasons  of  the  two  places,  the  character  of  the  soils  (which  are  entirely 
different)  as  affecting  retention  of  water,  and  the  care  used  in  the  selec- 
tion of  seed.  These  conditions  are  apparently  all  more  favorable  for 
the  development  of  smut  in  the  former  region. 

In  the  same  locality  there  may  be  a  considerable  variation  from 
year  to  year.  For  example,  in  the  hard  pan  district,  the  counts  in  1897 
showed  an  average  loss  of  11%,  while  the  next  year  this  dropped  down 
to  4%.  As  explained  before  these  differences  are  largely  due  to  seasonal 
variations. 

In  the  same  locality  there  may  be  quite  a  wide  variation  between 
different  fields,  as  is  shown  by  an  inspection  of  the  figures  given  in  the 
table.  While  the  character  of  the  seed  used  may  explain  in  part  this 
difference,  still  some  of  it  is  due  to  difference  in  time  and  manner  of 
planting,  moisture,  the  soil,  etc. 

The  average  of  the  counts  made  in  all  parts  of  the  state  is  6%. 
This  is  probably  a  little  higher,  rather  than  lower,  than  the  actual  loss 
year  after  year,  as  but  few  counts  were  made  in  northern  Illinois,  which 
is  more  like  the  central  than  the  southern  part  of  the  state  in  this  respect. 
This  per  cent,  is  a  little  lower  than  is  usually  made  for  other  states.  The 
average  yearly  value  of  the  oat  crop  in  this  state  for  1895-1898,  as  taken 
from  the  reports  of  the  U.  S.  Dept.  of  Agr.  was  about  $15,500,000.  If 


300 


BULLETIN    NO.     57. 


[March, 


TABLE  2.     PER  CENT.  OF  SMUT  IN  ILLINOIS  OAT  FIELDS,  1892-1898. 


No. 

Date. 

Locality. 

Total 
counts. 

No. 
smutty. 

% 

smutty. 

i 

1802 

Urbana  Kxperiment  Station.  ...        .        .    . 

700 

2 

Yz 

3 

!• 

•i                 ii                 ii 

c 

4 

ii 

..                 ii                 ii 

2 

5 

ii 

i. 

2 

6 

ii 

ii                 ii                 ii 

2 

7 

.i 

.1    '             ..                 ii 

O 

8 

.. 

i. 

O 

9 

.i 

ii                 ii                 .i 

a 

io 

ii 

•I                 ii                 ii 

800 

IO7 

I  a 

ii 

189  <; 

.i                 .i                 ii 

IOOO 

2O 

2 

12 

.. 

IOOO 

4O 

4^ 

13 

ii 

ii                 ii                 ii 

I  TOO 

18 

2 

ii 

ii                 ii                 i< 

QOO 

IO 

x 

I  c 

,i 

ii                 ii                 ii 

I5OO 

7 

J4 

16 

,. 

••                 ii                 .i 

I5OO 

22 

i 

17 

ii 

ii 

o 

o 

T8 

ii 

,.                 ii                 ii 

i 

IQ 

1896 

Polo  (Yeakel)  

cae 

12 

2 

20 

6S2 

18 

a 

21 

,i 

.1 

an  I 

2Q 

7 

22 

,, 

•  i 

^O3 

123 

21 

23. 

,. 

Odin  (Vaughn)  

I2O3 

252 

21 

24 

,, 

Farina  (McCluer)  

1287 

216 

IT" 

2? 

,, 

1477 

414 

28 

26 

,, 

Taylorville  (Shamel)  

1670 

342 

20 

27 

,, 

1422 

3l6 

22 

28 

,, 

Edgewood  (Bartley)  

IO3O 

3IO 

an 

2Q 

,, 

I59° 

299 

19 

an 

,i 

Champaign  County  

I7OO 

347 

2O. 

31 

,, 

4000 

86 

2t 

32 

., 

ii                 ii 

4200 

2QQ 

7 

33 

,. 

.i 

4000 

317 

8 

3,1 

ii 

n                 i> 

3000 

1  08 

4 

3C 

,i 

i.                 ii 

3000 

71 

2 

36 

,i 

•  i                 ii 

3000 

38-5 

13 

,, 

i.                 ii 

3; 

38 

,, 

.i                 ii 

s 

an 

i. 

,. 

5 

ii 

M                 ii 

5 

,, 

•  i                 ii 

5 

,, 

ii                 ii 

., 

,. 

3, 

,, 

ii                 .i 

2 

,, 

ii                 .i 

\ 

3 

46 

,, 

ii                 •• 

IO 

,, 

.i                 ii 

5 

48 

,, 

i. 

7 

,, 

ii                 ii 

8 

,, 

•  i                 ii 

5 

,, 

ii                 ii 

4 

,, 

ii                 ii 

i 

^3 

., 

.. 

3000 

439 

15 

i, 

ii                 ii 

5 

,, 

.i                 i. 

8 

16 

,, 

., 

2 

,, 

ii                 ii 

I 

"?8 

I 

3 

60 

,, 

i.                 ii 

i 

61 

,, 

•  I                 i. 

i 

/poo.  ] 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


301 


TABLE  2.     PER  CENT.  OF  SMUT  IN  ILLINOIS  OAT  FIELDS,  1892-98. — Continued. 


No. 

Date. 

Locality. 

Total 
counts. 

No. 

smutty. 

% 
smutty. 

62 

1896 

Champaign  County           .    .    . 

10 

63 

1807 

Urbana  to  Tuscola  

2=500 

37 

i 

$4 

2000 

3° 

2 

65 

,. 

.. 

2000 

48 

2 

66 

,, 

it                   ii 

2OOO 

K.C 

3 

f>7 

,. 

.. 

2500 

20 

I 

fi8 

., 

.• 

2OOO 

7 

y. 

69 

,, 

ii 

2OOO 

223 

ii 

70 

,, 

ii                   •> 

2OOO 

179 

71 

,, 

•  i                    ii 

IOOO 

103 

IO 

72 

i. 

ii 

2OOO 

97 

c 

73 

,, 

i,                    ii 

2OOO 

26 

I 

74 

,, 

Neoga  to  Sigel  

2OOO 

315 

16 

75 

,, 

2OOO 

401 

20 

76 

,. 

ii 

2OOO 

239 

12 

77 

.•• 

ii              ii 

2OOO 

iqo 

IO 

78 

,, 

i.              .1 

2OOO 

82 

79 

,, 

ii              .i 

2OOO 

37 

2 

80 

,, 

ii              <i 

2OOO 

75 

«T 

,', 

Sigel  to  Effingham  

2OOO 

500 

25 

8? 

,, 

IOOO 

238 

24 

8? 

,, 

•  i                  ii 

2OOO 

264 

13 

81 

,, 

I. 

2OOO 

382 

iq 

•85 

,, 

i.                  .. 

2OOO  • 

246 

12 

#fi 

,, 

ii 

2OOO 

239 

12 

#7 

,, 

ii 

IOOO 

68 

7 

88 

,, 

.. 

I  C.OO 

190 

13 

89 

,, 

.. 

2OOO 

144 

7 

9° 

,, 

ii 

IOOO 

J«52 

1C 

91 

,, 

ii                  ii 

IOOO 

109 

II 

92 

,, 

i. 

IOOO 

96 

IO 

93 

., 

Effinghara  to  Vandalia  

l8oO 

348 

IQ 

94 

., 

l6oO 

33 

2 

qc 

i, 

ii                     i< 

l6oO 

125 

8 

96 

,, 

i.                     i. 

Q4 

6 

97 

,. 

ii 

l6oO 

182 

ii 

98 

,, 

•  •                     i. 

l6oo 

179 

ii 

99 

,, 

ii 

l6oO 

IO2 

6 

loo 

,, 

i.                     K 

l6oO 

237 

1C 

101 

,, 

i. 

l6oO 

8 

y* 

IO2 

., 

i.                     ii 

l6oO 

307 

ig 

103 

,, 

•  •                     ii 

l6oO 

389 

24 

104 

,, 

.i                     ii 

I6OO 

435 

27 

IO5 

,, 

•  i                     ii 

l6oo 

2  "59 

16 

1  06 

,, 

.•                     i. 

l6oO 

255 

16 

IO7 

,, 

ii                     ii 

I6OO 

232 

1C 

1  08 

,, 

ii                     ii 

l6oO 

164 

IO 

109 

., 

., 

l6oO 

118 

7 

no 

., 

ii 

l6oO 

187 

12 

in 

•  i 

l6oO 

39 

2 

112 

,. 

•  i 

l6oO 

245 

1C 

113 

:, 

Vandalia  to  Pana     

I2OO 

I2O 

IO 

114 

,, 

1  7OO 

214 

13 

115 

,, 

ii 

I6OO 

123 

8 

TTfi 

,, 

,, 

I6OO 

128 

8 

117 

II 

.. 

1600 

145 

q 

TT8 

,| 

•  i                 .< 

l6oO 

253 

16 

119 

,, 

,. 

I6OO 

55 

3 

120 

., 

.i                 ii 

l6oO 

97 

6 

121 

,, 

ii                 ii 

l6oO 

80 

c 

122 

.. 

,. 

1600 

181 

II 

302 

TABLE  2. 


BULLETIN    NO.    57. 


[March, 


PER  CENT.  OF  SMUT  IN  ILLINOIS  OAT  FIELDS,  1892-1898. — Continued. 


No. 

Date. 

Locality. 

Total 
counts. 

No. 
smutty. 

% 

smutty. 

123 

1807 

Vandalia  to  Pan  a  

1600 

224 

124 

1600 

I  5O 

125 

ii 

•  I                 .1 

1600 

365 

23 

126 

ii 

ii                 ii 

1600 

222 

127 

ii 

.1                 ii 

1600 

290 

18 

128 

ii 

.. 

1600 

IO,6 

12 

I2Q 

i. 

ii                 ii 

1600 

8s 

e 

I  3Q 

ii 

•  i                 ii 

1600 

34 

2 

131 

ii 

ii                 n 

1600 

117 

7 

132 

•  I 

.i 

1600 

60 

133 

ii 

Pana  to  Decatur  

1600 

77 

e 

134 

•  i 

1600 

146 

Q 

13"? 

•  • 

ii              ii 

1600 

IQ2 

12 

T3fi 

•  i 

i. 

1600 

321 

2O 

1^7 

•  i 

ii              .1 

1600 

CT 

3 

738 

ii 

•  i              K 

1600 

5° 

3 

I3Q 

ii 

.            II                                     I! 

1600 

1  80 

I  I 

I4O 

I! 

ii              ii 

1600 

455 

28 

141 

•  1 

I!                                     .. 

1600 

46 

3 

142 

•  1 

i, 

1600 

370 

24 

143 

II 

•  i              ii 

1600 

257 

16 

144 

I 

•  i              i. 

1600 

QO 

6 

145 

I 

.. 

1600 

476 

3° 

146 

1        1 

ii«           <i 

1600 

68 

4 

147 

• 

ii              ii 

1600 

132 

8 

118 

I 

Decatur  to  Cerro  Gordo  

1600 

71 

I4Q 

II 

1600 

Q4 

6 

ICQ 

•  I 

.1                       ii 

1600 

60 

151 

1. 

.i 

1600 

18 

i 

IC2 

II 

H                                                           1! 

1600 

80 

• 

153 

II 

i.                       .i 

1600 

63 

A 

154 

II 

"                       "             

1  200 

QI 

8 

155 

II 

Champaign  County  

2OOO 

4O 

2 

156 

.1 

2OOO 

8 

y2 

157 

<l 

ii                 ii 

2OOO 

16 

i 

158 

'I. 

i.                 ii 

2OOO 

65 

3 

ICQ 

II 

•  i                 •< 

2OOO 

40 

2 

160 

II 

ii                 i> 

IOOO 

12 

I 

TfiT 

II 

.. 

I2OO 

5 

l62 

II 

.• 

I2OO 

26 

2 

163 

•  1 

New  Windsor  

1  154 

20 

2 

l64 

II 

Elva  

7?8 

44 

6 

165 

1, 

Geneseo  

877 

•\ 

i  , 

166 

! 

Norwood  •.  

521 

13 

2 

Tfi? 

• 

Melville  

1046 

38 

4 

1  68 

I 

Delavan  

I3O6 

16 

I 

160 

I 

Oneida  

830 

s 

I 

I  7O 

1 

Elva  

713 

27 

4 

171 

. 

Womac          

1066 

c 

', 

172 

, 

Macon  .         

1  144 

32 

3 

173 

I 

Malta  

803 

19 

2 

174 

1 

Washburn  

1217 

39 

3 

175 

1 

Decatur  .•  

859 

42 

5 

176 

I 

Argenta  

883 

10 

r 

177 

I 

Sycamore    

008 

14 

2 

178 

.1 

Pana    i 

ICH3 

7° 

7 

I7Q 

1, 

Beecher       

789 

•ji 

4 

180 

II 

Jerseyville  

I  III 

6l 

5 

r8r 

II 

Clear  Creek  

1225 

22 

2 

T8? 

II 

Wasco  

900 

14 

2 

783 

II 

Taylorville  i 

1172 

2O 

2 

IQOO.  ] 
TABLE  2. 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


3°3 


PER  CENT   OF  SMUT  IN  ILLINOIS  OAT  FIELDS,  1892-1898.  —  Continued. 


Date. 


Locality. 


1897        Elmwood 995  9 

Mt.  Carroll 794  i 

Bishop 826  4 

Polo 1474  18 

Richview "    840  17 

Panola 744  o 

Canton 950  7 

Plainfield 736  10 

Bellville 1353  i 

Edge  wood 1266  99 

Melville   1258  4 

Springfield 1013  49 

Moweaqua 853  34 

Ashley  to  Irvington 2000  39 

1700  149 

1900  84 

1500  57 

2OOO  69 

Centralia  to  Kinmundy 2000  36 

2000  21 

2000  116 

2000  6 1 

1500  2 

1700  105 

2000  55 

2COO  82 

2OOO  42 

2OOO  14 

1900  113 

20OO  IO5 

2OOO  41 

2OOO  52 

I50O  26 

200O  139 

Mason  to  Effingham 2000  156 

2000  44 

2000  171 

2OOO  80 

2OOO  40 

20OO  46 

2000  97 

2000  66 

2000  68 

2OOO  115 

2000  7 1 

2OOO  89 

2000  59 

2OOO  131 

200O  87 

20OO  114 

2000  86 

2OOO  155 

2OOO  82 

Champaign  County 2000 

2OOO  36 

2000  73 

2000  54 

2000  77 

2000  88 

2000  44 

2000  68 


Total 
counts. 


No.  % 

Smutty.   Smutty. 


3°4 


IHJLl.ETIN     NO.     57. 


{March, 


TABLE  2.    PER  CENT.  OF  SMUT  IN  ILLINOIS  OAT  FIELDS.  1892-1898. — Continued. 


No. 


245 
246 
247 
248 
249 
250 

251 
252 

253 
254 
255 
256 
257 
258 

259 
260 
261 
262 
263 
264 
265 
266 


Date. 


Locality. 


1898  I     Champaign   County. 


Total 


No. 


counts,     smutty. 


2000 
2000 

20OO 
2OOO 
2000 
2000 
2OOO 
2OOO 
2OOO 
20OO 
200O 
20OO 
2OOO 
2OOO 
2OOO 
2000 
2000 
2000 
2000 
2OOO 
20OO 
2000 


42 
66 

102 

26 

66 
84 
78 
3 
17 

22 
9 

5 

7 
16 

13 

32 

3 

o 

22 
12 
40 


smuttv. 


6%  represents  the  average  loss  it  would  mean  that  this  fungus  cost  the 
farmers  of  this  state  during  that  time  about  a  million  dollars  a  year. 

The  injurious  effect  of  smut  upon  this  host  is  shown  by  the  weights 
and  measures  given  in  Table  3.  These  were  taken  from  all  of  the  oats 
grown  on  two  small  plats  under  similar  conditions,  except  that  one  plat 
was  considerably  more  than  half  smutted,  while  the  other  was  practically 
free.  The  figures  show  that  the  loss  of  grain  may  be  partial  or  entire 
for  an  infected  plant  (all  the  culms  from  one  stool),  in  this  case  the 
wholly  smutted  plants  greatly  outnumbering  those  only  partially  smutted; 

TABLE  3.     EFFECT  OF  SM^T  ON  OATS. 


Plat. 

N  -  ' 

Plants. 

Weight 
of  entire 
plants. 

Ratio 

weight  per 
100  culms 

Weight 
of 
grain. 

Ratio 

weight  per 
100  culms. 

No. 
plants 

No. 
culms 

179 

Average 
No.  culms 
per  plant 

Average 
length 
of  culms 

•«.< 

^)    (T> 

i-+»  r 
o  3 
»  e 
w   £ 

•  ^ 

Smut 
free 

2I>£    OZ 

12 

5  oz. 

3 

41 

4-4 

49  in. 

Partially 
smutted. 

71A  oz 

8 

I   OZ. 

i 

16 

90 

5-6 

*44  in 

Wholly 
smutted. 

26  oz. 

7 

o  oz. 

o 

99 

358 

3-6 

40  in. 

I  ^^ 

3  n>  2 

r"  S 
o  5  ' 

3  £ 
•< 

Smut 
free. 

59  oz. 

13 

iSX  oz. 

3 

no 

462 

4-2 

48  in. 

Wholly 
smutted 

#oz. 

9 

0 

o 

2 

8 

4- 

45io 

Partially 
smutted. 

No  plants. 

^Average  length  smutted  40,  of  free  48  inches. 

that  the  weight  of  smutted  culms  is  less  than  that  of  the  free,  while  their 
length  is  reduced  on  the  average  several  inches.      There  is  some  qnes- 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


305 


tion  as  to  its  effect  on  the  stooling  habit,  since  the  average  number  of 
culms  per  plant  for  those  entirely  smutted  was  less  than  for  those 
entiiely  free,  while  the  partially  smutted  averaged  higher  than  either. 

EXPERIMENTS. 

Miscellaneous  Experiments.  As  is  shown  in  Table  2  there  may  be 
a  considerable  variation  in  the  amount  of  smut  in  different  fields  in  the 
same  locality.  Undoubtedly  this  is  not  due  entirely  to  the  character  of 
the  seed  sown,  since  in  some  known  cases  where  the  same  seed  has  been 
used  such  differences  have  still  appeared.  It  was  to  study  these  varia- 
tions, and  determine  as  far  as  possible  their  causes,  that  in  1897-8  a 
number  of  different  experiments  were  conducted. 

TABLE  4.     RELATION  OF  TIME  OF  PLANTING  OATS  TO   %   OF  SMUT.     1897. 


Ordinary  seed. 

Row  i. 

Row  2. 

Row  3. 

Aver. 

o> 

Plat. 

Date  of 
planting. 

Total 
counts 

No. 
smutty 

% 

smutty 

Total 
counts 

No. 
smutty 

% 

smutty 

Total 
counts 

No. 
smutty 

% 

smutty 

/° 
smutty 

i 

March  22 

850 

12 

i 

910 

7 

i 

742 

7 

i 

i 

2 

29 

384 

13 

3 

639 

8 

i 

864 

3i 

4 

3 

3 

April        5 

656 

4 

i 

590 

ii 

2 

654 

20 

3 

2 

4 

13 

592 

6 

i 

609 

8 

I 

611 

25 

4 

2 

5 

19 

539 

19 

4 

646 

19 

3 

645 

15 

2 

3 

6 

26|    195 

0 

o 

696 

5 

i 

684 

8 

I 

2/3 

7 

May        4 

513 

10 

2 

502 

12 

2 

617 

22 

4 

3 

8 

"     .10 

353 

17 

5 

448 

I 

# 

5i5 

7 

i 

2 

9 

17 

447 

14 

3 

533 

13 

2 

654 

ii 

2 

2 

10 

24 

151 

2 

2/3 

J35 

O 

O 

65 

o 

O 

g 

Very  smutty  seed 


I 

April   5 

874 

92 

ii 

898 

1  06 

12 

807 

I2O 

15 

13 

2 

13 

798 

138 

17 

792 

107 

14 

1062 

172 

16 

16 

3 

19 

860 

117 

14 

939 

in 

12 

94° 

IOO 

ii 

12 

4 

26 

658 

38 

6 

700 

101 

J4 

807 

81 

10 

IO 

5 

May    4 

633 

76 

12 

659 

104 

16 

800 

105 

13 

»4 

6 

"     10 

507 

21 

4 

622 

34 

5 

640 

64 

IO 

6 

7 

17 

400 

40 

10 

597 

64 

ii 

807 

H5 

14 

12 

8 

24 

334 

29 

9 

330 

23 

7 

443 

48 

II 

9 

9 

3i|  197 

9 

5 

275 

16 

6 

270 

14 

5 

5 

One  of  the  most  extensive  of  these  experiments  was  the  planting  of 
the  same  seed  oats  at  different  dates  to  determine  if  time  of  planting 
had  an  influence  on  amount  of  smut.  In  1897  two  lots  of  oats,  one  of 
quite  smutty  and  the  other  of  supposedly  rather  clean  seed,  were  sown 
each  week  for  a  series  of  ten  weeks.  Care  was  used  to  plant  the  seed 
as  nearly  as  possible  alike  each  time  and  each  planting  was  made  in 
three  rows — the  per  cent,  of  smut  being  determined  for  each  as  well  as 
their  average — to  serve  as  checks  on  each  other.  While  there  was  some 
variation  between  the  different  weeks  (Table  4)  it  was  not  always 
uniformly  marked  in  the  three  rows,  except  in  the  case  of  the  seed 
planted  very  late,  May  24th  and  after,  in  which  cases  the  smut  was 
undoubtedly  decreased. 

This  same  experiment  was  repeated  again  in   1898  (Table  6)  when 


3°<5 


BULLETIN    NO.     57. 


[March, 


only  very  smutted  seed  was  used,  as  such  variation  would  be  most  likely 
to  manifest  itself  with  this.  The  seed  was  planted  in  duplicates  in  three 
different  ways  for  a  series  of  eight  weeks.  It  was  again  shown  in  every 
case  that  the  very  late  plantings  (on  and  after  May  i6th  this  year)  had 
lowered  the  per  cent,  of  smut.  This  year  the  first  planting  seemed  to 
have  been  similarly  affected.  The  variations  between  the  plantings 
made  within  the  proper  season  were  like  those  of  the  preceding  year  ; 
that  is,  not  so  marked  and  uniform,  but  doubtless  due  in  part  to  the 
difference  in  time  of  planting. 

This  effect  of  late  planting  was  also  noticed  in  other  experiments 
carried  on  in  1898.-  The  same  seed  planted  in  season  gave  6-10%  smut, 
while  that  planted  far  out  of  season  had  this  reduced  to  less  than  2%. 
In  the  examination  of  fields  just  before  harvest  it  has  also  been  noticed 
that  those  that  were  yet  far  from  being  ripe,  indicating  an  unusually  late 
planting,  gave  the  lowest  per  cents,  of  smut.  It  is  also  claimed  by  some 
farmers  that  where  "freezing  in"  the  seed,  is  practiced  there  is  less  smut 
than  when  the  same  seed  is  sown  later. 

The  proper  explanation  of  this  reduction  in  per  cent,  of  smut  in 
oats  planted  out  of  season  seems  to  be,  in  part,  that  fewer  plants  are 
originally  infected,  because  the  amount  of  moisture  at  the  time  of  later 
plantings  is  not  so  great  and  in  .the  earlier  ones  the  heat  conditions  are 
not  so  favorable,  but  also,  in  part,  to  the  fact  that  oats  planted  out  of 
season  have  very  unfavorable  conditions  for  growth  and  those  that  have 
both  the  smut  and  these  to  combat  would  be  most  likely  to  succumb. 

In  1897-8  experiments  were  also  carried  on  to  determine  if  manner 
of  planting  affected  the  per  cent,  of  smut.  The  experiments  of  1897 
(consisting  of  planting  seed  one,  two,  four  and  six  inches  deep,  see 
Table  5)  were  not  very  extensive  and  did  not  show  any  marked  differ- 
ence in  per  cent,  of  smut. 

The  more  extensive  experiments  of  1898,  however,  gave  some  very 
interesting  results  that  can  only  be  attributed  to  the  manner  of  sowing 

TABLE  5.     RELATION  OF  DEPTH  OF  PLANTING  OATS  TO  %   OF  SMUT.     1897. 


Plat. 

Counts. 

One  inch  deep. 

Two  inches  deep. 

Four  inches  deep. 

Six 
inches 
deep. 

Row  i 

Row  2 

Aver- 
age. 

Row  i 

Row  2 

Aver- 
age. 

Row  i 

Row  2 

Aver- 
age. 

)rdinary 
seed 

Total  counts.  .  .  . 
Number  smutty. 
Per  cent,  smutty 

590 
32 
5 

579 
42 
7 

449 

20 

4 

515 
22 

4 

492 

21 

4 

541 
32 

6 

191 
16 

8 

"e 

5 

_4_ 

Smutty 
seed. 

Total  counts  .  .  . 
Number  smutty. 
Per  cent,  smutty 

634 
in  . 
18 

612 

?i 

12 

582 
67 

12 

728 
84 
12 

329 
49 
15 

272 

37 
M 



5i 
7 
14 

15 

12 

H 

the  seed,  since  the  experiments  were  carried  on  in  duplicate  through  a 
series  of  eight  weeks  and  uniformly  gave  the  same  result  till  lateness  of 
planting  blotted  out  the  differences.  This  year  the  seed  was  sown  in 


i  goo.'} 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


3°7 


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S3 

BULLETIN    NO.     57. 


[March, 


three  different  ways:  namely,  broadcast,  lightly  covering  by  raking  over 
the  ground;  in  rows  one  inch  deep;  and  in  rows  four  inches  deep. 
Table  6  shows  that  uniformly  the  seed  sown  broadcast  gave  a  low  per 
cent,  of  smut,  an  average  of  2%,  that  one  inch  deep  a  much  higher 
per  cent.,  averaging  6%,  while  that  four  inches  deep  gave  a  quite 
smutty  crop,  averaging  10%.  The  same  seed,  in  a  different  experi- 
ment, sown  broadcast  and  then  harrowed  in  gave  about  the  same  per 
cent,  as  that  planted  one  inch  deep. 

Such  differences  may  be  accounted  for  by  the  differences  in 
amount  of  available  moisture  and  the  exposure  of  the  seed  germ. 
The  seeds  planted  four  inches  deep  had  the  most  moisture  and  the 
germs  were  exposed  through  a  greater  length  and  for  a  longer  time, 
as  it  took  one  or  two  days  longer  for  them  to  appear  above  ground. 
On  the  other  hand  these  conditions  least  obtained  with  the  seed  sown 
broadcast  and  scarcely  covered. 

While  it  is  true  that  character  of  season  and  manner  of  planting 
may  be  factors  in  the  determination  of  the  per  cent,  of  smut,  the  most 
important  factor  is  the  relation  of  the  seed  to  the  position  and  number 
of  smut  germs  attached  to  it.  The  results  given  in  Table  7  show  some 
interesting  data  along  these  lines. 

In  the  first  place  it  is  shown  that  it  is  the  smut  attached  to  the  seed 
that  causes  infection,  and  not  any  that  may  be  in  the  land  or  blown  to 
the  plant.  Those  plats  that  had  the  seed  treated  gave  free  crops,  and 
those  that  had  more  or  less  living  smut  attached  to  seed  gave  a  more  or 
less  smutty  crop. 

While  numbers  of  spores  present  were  significant  their  position 
seemed  to  be  of  more  importance.  The  glumes  are  of  great  advantage 
in  protecting  the  seed  germ  at  the  very  first  from  all  the  smut  germs  on 
the  outside.  After  the  seed  has  matured  it  is  not  very  easy  for  spores 

TABLE  7.     RELATION  OF  SMUT  GERMS  TO  SEED  IN  INFECTION. 


Plat. 

Kind  of  treatment  given  the  seed. 

Total 
counts. 

No. 

smutty. 

% 
smutty. 

5 

6 

7 

8 

9 
10 
ii 

12 

Hot  water  treated  seed  of  1897  treated  again 
in  1898,  132°  F.  for  7  minutes  

Practica 
Practica 
4000 
Practica 

3400 

2500 

720 

875 

ly  free. 
ly  free. 
76 
lly  free. 

322 
5° 

513 
9 

0 

o 

2 

o 
9 

2 

71 

I 

Same  as  5  but  not  treated  in  1898.  

Untreated  seed  of  1897  having  20  %  smut.  .  . 
Same  as  7  but  treated  in  1898,  132°  F.  for  7  min. 
Same  as  6  but  mixed  wet  with  smut  when 
planted  

Same  as  6  but  mixed  dry  with  smut  as  soon 
as  ripe            

Same  as  6  but  seeds  hulled  and  mixed  wet 
with  smut  just  before  planting  

Same  as  n,  but  seeds  not  mixed  with  smut.  . 

to  be  carried  down  between  the  tightly  enveloping  glumes.   As  has  been 
claimed  by  other   experimenters  it   is  chiefly  the   smut  that  falls  down 


/poo.] 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


3°9 


TABLE  8.     TIME  OF  APPEARANCE  OF  OAT  SMUT. 


between  the  glumes  when  they  are  normally  open  in  the  field  that  causes 
the  damage.  Experiments  in  plats  9-11  well  illustrate  this.  In  plat  10 
oat  seed  that  was  obtained  from  a  field  free  from  smut  was  abundantly 
mixed  with  dry  spores  as  soon  as  gathered.  This  gave  2%  of  smut 
next  year.  The  same  kind  of  seed  when  mixed  wet  with  spores  just 
before  planting  (a  treatment  that  would  carry  more  of  the  spores  inside 
the  glumes  than  the  dry  mixing)  gave  9%  of  smut.  The  seed,  however, 
that  had  the  glumes  removed  and  was  then  mixed  wet  with  smut  gave 
71%,  a  percentage  rarely  ever  equalled.  The  lot  hulled  but  not  mixed 
with  smut  gave  only  i%. 

Table  8  gives  the 
results  of  an  experi- 
ment to  determine 
time  of  appearance 
of  the  smutty  pani- 
cles of  oats.  It  is 
claimed  by  some 
that  certain  smuts 
hasten  maturity  of 
theplant,  thesmutty 
panicles  being  the 
first  to  appear.  The 
examinations  of  the 
cases  given  here 
were  made  on  two 
different  dates,  the 
first  soon  after  the 
earliest  panicles  be- 
gan to  appear  and 
the  second  after 
they  were  all  out.  The  results  show  that  with  oats  the  influence  of  the 
smut  is  retarding  rather  than  accelerating. 

Prevention  Experiments.  The  aim  of  the  work  in  prevention  of  oat 
smut  has  been  to  determine  the  most  efficient  and  at  the  same  time  the 
most  practical  of  known  remedies  rather  than  to  discover  any  new  fun- 
gicide. The  first  experiments  were  made  in  1895,  at  which  time  noth- 
ing had  been  done  by  the  Station  in  this  direction,  although  a  good 
deal  of  successful  experimentation  had  been  made  by  some  other 
stations.  For  the  first  two  years  only  the  hot  water  treatment  was  tried. 
The  amounts  of  seed  treated  varied  from  a  few  quarts  up  to  a  bushel 
and  a  half.  The  treatments  proved  uniformly  successful  in  practically 
preventing  the  smut.  Details  of  the  treatments  and  counts  from  treated 
and  check  plats  are  given  in  Table  9. 


[une  21,  ' 

97- 

J 

une  30,  ' 

97- 

Plat. 

Total 
culms. 

No. 
smutty. 

% 
smutty. 

Total 
culms. 

No. 
smutty. 

% 

smutty. 

i 

39° 

19 

5 

874 

92 

ii    • 

2     . 

525 

26 

5 

898 

1  06 

12 

3 

290 

4 

2 

807 

1  20 

15 

4 

286 

6 

2 

798 

138 

17 

5 

254 

6 

2 

792 

107 

M 

6 

299 

10 

3 

1062 

172 

16 

7 

500 

2 

1 

850 

12 

i 

8 

6.55 

4 

1 

910 

7 

5 

9 

489 

0 

O 

742 

7 

I 

Av 

erage   . 

2 

Aver 

age   . 

IO 

Plat. 

fune  18,  ' 

98. 

July  8.  'g 

8. 

i 

1700 

13 

1 

3275 

42 

i 

2 

750 

7 

I 

1850 

49 

3 

3 

200 

2 

I 

1580 

43 

3 

4 

20 

6 

30 

720 

513 

7i 

Av 

erage 

8 

Aver 

age 

20 

310  BULLETIN  NO.   57.  [March, 

TABLE  9.     RESULTS  OF  HOT  WATER  TREATMENT  FOR  OAT  SMUT.     1895-6. 


Plat. 

Treatment  given  seed. 

Smutty. 

Total* 
counts: 

% 

smutty. 

I. 

i32°-i35°  F.  for  15  minutes,     i  peck  

2 

28,  341 

o 

II. 

Check  plat.     Untreated  

^8 

2ci,24I 

i  ^ 

i 

i29°-i3o°  F.  for  10  minutes,     i  gallon 

T. 

27,  SOO 

o 

2 

Check  plat.    Untreated  ....    

6OO 

36,OOO 

1  .7 

3 

i32°-i^3°  F.  for  10  minutes,      i  gallon  

I 

23,OOO 

o 

4 

Check  plat     Untreated  

35O 

l8,OOO 

2 

5 

I34°-I36°  F.  for  15  minutes,     i  gallon  

3 

29,  ooo 

O 

A 

131°  F.  for  8  minutes,     i^  bushels  

28 

224,OOO 

O 

B 

Check  plat.    Untreated  

128 

4,  TOO 

3 

C 
D 

I3o°-i55°  F.  for  8  minutes.     \yz   bushels.  .  . 
Check  plat.    Untreated  

53 

378 

38o,OOO 
6,700 

o 
5-6 

*These  are  mostly  estimated  from  counts  of  parts  of  the  plats. 

The  results  with  hot  water  having  been  so  satisfactory,  as  far  as 
preventing  smut,  it  was  decided  in  the  experiments  conducted  in  1897 
to  compare  this  treatment  with  the-  other  most  promising  ones  recom- 
mended by  various  experimenters  with  the  hope  of  determining  if  it 
were  the  most  practical  as  well  as  the  most  efficient  method.  In  these 
experiments  ten  pounds  of  very  smutty  seed  was  treated  in  each  case 
and  then  planted  in  one-fifth  acre  plats.  (See  Table  10).  That  treated 
by  sprinkling  was  made  very  thorough.  With  the  copper  sulfate  treat- 
ment half  the  seed  was  mixed  with  air  slaked  lime  to  help  dry  it  and 

TABLE  10.     VARIOUS  TREATMENTS  FOR  PREVENTION  OF  OAT  SMUT.     1897. 


Plat. 

Treatment  given  seed. 

Smutty. 

Total 
counts. 

% 

smutty. 

i 

Hot  water,  i34°-i32°  F.  for  8  minutes  

Found  20 
in  £  acre 

smutted 
plat. 

o 

2 

Potassium  sulfid,  thoroughly  sprinkling,  rate 
of  i  Ib.  to  12  gals,  water  

113 

3000 

3.8 

3 

Ceres  pulver,  thoroughly  sprinkling,  rate  of 
i  Ib.  to  12  gals,  water  

74 

3400 

2.2 

4 

Copper  sulfate,   thoroughly  sprinkling,   rate 
i  Ib.  to  5  gals,  water  

16 

3900 

.4 

41 

Copper  sulfate,  same  as  4,  but  limed  shortly 
after  treatment  

9° 

4700 

I  .9 

5 

Check  plat.    Untreated  

678 

3300 

2O.5 

also  to  stop  action  of  chemical.  The  seed  came  up  about  the  same 
in  all  the  plats  except  the  unlimed  half  of  the  seed  treated  with  copper 
sulfate.  In  this  case  the  action  of  the  chemical  had  been  too  severe, 
killing  part  of  the  seed  and  greatly  retarding  the  germination  of  all  by 
destroying  the  root  end  of  the  embryo.  This  seems  to  be  a  not  un- 
common effect  of  this  chemical.  The  results  show  each  treatment 
effective  in  lessening  the  amount  of  smut;  but  the  hot  water  by  far  the 
most  successful.  The  sprinkling  methods,  however,  had  been  found  to 
be  less  cumbersome.  Here  the  seed,  while  not  so  thoroughly  wet  as  in 


IQOO.  ] 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


the  hot  water  treatment,  was  still  dampened  enough  to  require  attention 
in  drying  or  in  sowing,  if  sown  immediately. 

In  1898  the  experiments  for  comparing  the  best  methods  of  treat- 
ment were  conducted  on  a  more  extensive  scale.  The  results  are  given 
in  Table  n.  Seed  which  had  10%  smut  in  it  the  year  before  was  used, 
and  the  same  amount  was  sown  on  plats  of  one-seventeenth  of  an  acre. 
Except  the  hot  water,  such  treatment  was  by  thoroughly  sprinkling  at 
the  rate  of  between  one  and  two  gallons  of  liquid  per  bushel  of  seed. 
The  seed  was  then  placed  in  boxes  and  two  days  later  planted,  except 

TABLE  n.     VARIOUS  TREATMENTS  FOR  PREVENTION  OF  OAT  SMUT.     1898. 


Plat. 

Treatment  given  seed. 

Smutted. 

Total 
counts. 

% 
smutted. 

i 

2 

3 
4 
5 

Corrosive  sublimate,  i  Ib.  to    25  gals,  water. 
"                     i  Ib.  to    50  gals,  water, 
i  Ib.  to  100  gals,  water. 
"      same  as  2,  planted  immediately. 
Check  plat.    Untreated           ....        

105 

158 
237 
135 
230 

4000 
4000 
4000 
4000 
4000 

2.6 

4 
5-9 
3-4 

5-8 

6 

7 
8 

9 

10 

Formalin,  i  Ib.  to    25  gals,  water  

(  Not  a  smutted   ) 
(        panicle.          f 
j      21  smutted       1 
(  panicles  in  plat  \ 
506           4000 
(       7  smutted       | 
(   panicles  in  plat  \ 
440           4000 

0 

o 

12.7 

0 

II 

i  Ib.  to    50  gals,  water   

i  Ib.  to  100  gals,  water  

•"        Same  as  7,  but  planted  immediately 
Check  plat.    Untreated  

ii 

12 

13 
14 
15 

16 

Copper  sulfate,  i  Ib.  to    5  gals,  water  

I     78  sm 
/  panicle 
36 

22 
125 

42 

357 

utted       ) 
3  in  plat  i 
4000 
4000 
4000 
4000 
4000 

o 

.9 
•  5 
3-1 
i  .  i 
8.9 

i  Ib.  to  10  gals,  water.  Unlimed 
"           i  Ib.  to  10  gals,  water.     Limed, 
i  Ib.  to  15  gals,  water  

"  Same  as  12,  but  planted  immediately 
Check  plat.     Untreated  

17 
18 

19 

20 
21 

Ceres  pulver,  i  Ib.  to    5  gals,  water   

56 
70 
78 
60 
3i6 

4000 
4000 
4000 
4000 
4000 

1-4 
1.8 

2. 

i-5 
7-9 

i  Ib.  to  10  gals,  water  

i  Ib.  to  15  gals,  water  

Same  as  18,  planted  immediately 
Check  plat.    Untreated  

22 
23 

24 
25 
26 

Potassium  sulfid,  i  Ib.  to    5  gals,  water  
i  Ib.  to  10  gals,  water  
i  Ib.  to  15  gals,  water  
Same  as  23,  planted  immediately 
Check  plat.    Untreated  

52 
72 
68 
68 

202 

4000 
4000 
4000 
4000 
4000 

i.3 

1.8 

1-7 
1-7 
5-i 

27 

28 

Hot  water,  133°  F.  for  12  minutes  

j  Not  a  smutted    ^ 
j        panicle.          ( 
(      50  smutted       j 
1   panicles  in  plat  \ 

0 

o 

i3i°-2°  F.  for  6  minutes  

that  one  plat  for  each  chemical  used  was  planted  immediately.  This 
was  done  to  determine  whether  or  not  the  chemicals  were  used  in  strong 
enough  solutions  to  injure  germination  of  seed  if  left  damp  some  time, 


3I2 


BULLETIN    NO.     57. 


[March* 


or  whether  or  not  the  treatment  was  severe  enough  to  kill  the  smut  if 
seed  was  sown  immediately.  With  the  strengths  used  either  method 
proved  equally  efficient  and  harmless.  All  treated  plats  came  up  before 
checks,  and  so  far  as  could  be  told  from  a  general  examination  no- 
treatment  had  an  injurious  effect  on  germination,  unless  it  was  the 
stronger  solutions  of  corrosive  sublimate.  Three  strengths  of  each 
chemical  were  used  to  gain  some  idea  as  to  how  weak  or  strong  the 
solutions  could  be  made  and  still  be  efficient.  Potassium  sulfid  and 
Ceres  pulver  gave  about  the  same  results  as  in  1897,  cutting  down  the 
per  cent,  of  smut  considerably  but  in  no  case  making  it  less  than  one  or 
two  per  cent.  Corrosive  sublimate  was  not  as  effective  as  either  of 

TABLE  12.      FUMES  OF  FORMALIN  FOR  PREVENTION  OF  OAT  SMUT.     1898. 


Plat. 

Planted. 

Treatment  given  seed. 

Results. 

29 

April  15. 

10  %  formalin  sprinkled  at  rate  of 
i  quart  to  i  bushel,  sacked  and 
planted  at  end  of  6  hours 

Seed  entirely  killed. 

30 

April  16. 

Same  as  29,  but  planted  at  end  of 
24  hours. 

Seed  entirely  killed. 

32 

April  26. 

Same  as  29,  but  planted  at  end  of 
ii  days. 

Seed  entirely  killed. 

33 

April  26. 

One  pint  of  oats  wet  with  l/&  pint  of 
25  %  formalin  and  then  placed 
in  box  and  7  pints  of  smutty  oats 
placed  on  top.  Planted  i  quart 
taken  from  top  n  days  later. 

No  smut  was  found  in  this 
plat,  and  apparently  the 
treatment  had  not  in- 
jured germination  of 
oats 

34 

April  26. 

Same  as  plat  33,  except  y$  pint  of 
carbon  bisulfid  was  used. 

Counts  of  4000  panicles  gave 
151  smutty,  or  3.8  %  . 

35 

April  26. 

Check  plat.     Untreated. 

Counts  of  4000  panicles  gave 
215  smutty,  or  5.4  %  . 

36 

May  10. 

5  %  formalin  sprinkled  at  rate  of 
i  quart  to  i  bushel,  then  sacked 
and  planted  at  end  of  24  hours. 

Found  no  smut  in  this  plat,, 
but  germination  of  seed 
was  apparently  injured 
by  the  treatment. 

37 

May  10. 

2  %  formalin  sprinkled  at  rate  of 
i  quart  to  i  bushel,  sacked  and 
planted  at  end  of  24  hours. 

Found  no  smut,  but  this  and 
36  planted  too  late  to  tell 
exact  effect  on  seed 

38 

May  10. 

Check  plat.     Untreated. 

Counts  of  4000  panicles 
showed  78  smutty  or  z%  . 

39 

May  17. 

Same  as  plat  36,  but  planted  one 
week  after  treatment. 

Found  no  smut  in  this  plat, 
but  did  not  do  as  well  as 
check. 

40 

May  17. 

Same  as  plat  37,  but  planted  one 
week  after  treatment. 

Found  no  smut,  but  planted 
too  late  to  tell  effect  on 
seed. 

4i 

May  17. 

Check  plat.     Untreated. 

Counts  of  2000  panicles  gave 
28  smutty,  or  1.4  %. 

IQOO.~\  SMUTS    OF    ILLINOIS'    AGRICULTURAL    PLANTS.  313 

these,  and  it  has  the  further  objection  of  being  a  deadly  poison.  The 
stronger  solutions  of  copper  sulfate  were  quite  effective,  and  did  not 
seem  to  injure  the  grain  as  in  the  preceding  year.  The  formalin  and 
hot  water  treatment  gave  perfect  results  in  two  cases,  and  proved  their 
superiority  over  all  others. 

While  the  sprinkling  method  lacks  the  cumbersomeness  of  the  dip- 
ping method,  still  it  has  about  the  same  objection  against  it  as  regards 
wetting  the  seed.  To  make  the  treatment  efficient,  the  sprinkling  must 
be  thorough,  and  this  necessitates  drying  the  seed  afterward,  unless 
sown  immediately.  Most  seeders  will  not  work  well  with  wet  seed.  The 
character  of  formalin,  as  regards  its  very  pungent  fumes  and  its  ex- 
cellency as  a  fungicide,  suggested  that  perhaps,  if  used  in  stronger  solu- 
tions but  not  in  sufficient  quantity  to  dampen  the  seed,  it  might  still 
destroy  the  smut  without  injury  to  the  seed.  Experiments  along  this 
line  were  conducted  in  1898.  Usually  with  the  sprinkling  method  a 
gallon  or  more  of  the  liquid  is  used  per  bushel  of  grain.  In  these  ex- 
periments the  rate  was  only  a  quart  per  bushel,  which  was  not  sufficient 
to  wet  the  seed  so  but  that  it  could  be  sacked  and  left  without  drying. 
Different  strengths  of  solutions  were  used,  the  stronger  proving  fatal 
or  injurious  to  the  seed.  Most  of  the  treatments  were  made  so  late 
in  the  season  that  the  exact  effect  on  the  seed  and  smut  could  not 
be  told,  since  seed  planted  so  late  naturally  does  poorly  and  is  likely 
to  have  less  smut.  In  one  or  two  cases,  however,  (see  plats  33,  37, 
Table  12)  some  very  suggestive  results  were  obtained  and  offer  encour- 
agement for  further  investigation  along  this  line.  The  results  also 
show  the  comparative  inefficiency  of  the  fumes  of  carbon  bi-sulfid  in 
this  direction. 

Hot  Water  Treatment  in  southern  Illinois.  It  was  desired  to  find 
out  exactly  how  this  treatment  would  work  under  ordinary  farm  con- 
ditions both  as  to  the  prevention  of  smut  and  the  practicability  of  the 
method.  Accordingly  arrangements  were  made  in  1898  with  four  inter- 
ested farmers  in  different  localities  in  southern  Illinois  for  the  treatment 
of  a  limited  amount  of  seed  for  them  and  a  half  a  dozen  of  their  neigh- 
bors. Southern  Illinois  was  selected  because  here  during  the  two  pre- 
ceding seasons  the  loss  from  oat  smuts  had  been  considerable.  The 
arrangements  made  by  the  farmers  for  treating  the  seed  varied  some- 
what, but  ordinarily  consisted  of  a  fire  out  doors,  two  or  three  large  iron 
kettles  for  heating  the  water,  a  couple  of  barrels  for  dipping  the  grain, 
and  a  supply  of  water.  At  one  place  steam  was  provided  from  a  boiler 
by  means  of  which  a  large  tank  of  water  was  readily  heated  to  the 
desired  temperature.  Except  at  Du  Bois,  wnere  the  size  of  the  steam 
heated  tank  made  it  possible  to  treat  two  bushels,  only  one  bushel,  in  a 
large  coarse  gunny-sack,  was  treated  at  a  time.  This  was  generally 
given  a  preliminary  bath  in  a  barrel  of  hot  water  before  being  placed  in 


314  BULLETIN  NO.    57.  [ March  , 

the  barrel  at  the  required  temperature.      From  one  to  four  bushels  were 
treated  for  each  man,  about  sixty  bushels  being  treated  altogether. 

The  conditions  were  such  as  to  test  severely  the  feasibility  of  this 
method  of  treatment  as  an  ordinary  farm  operation.  The  farmers  were 
not  usually  provided  with  means  for  readily  drying  the  treated  seed  and 
the  season  being  a  very  damp  one  also  made  this  more  difficult.  Rain 
delayed  the  planting  in  some  cases  for  a  month  after  the  treatment. 
With  a  number  the  oats  had  germinated  rather  freely  before  planting, 
but  this  did  not  seem  to  have  caused  much  subsequent  injury.  Usually 
the  farmers  reported  the  germination  and  stand  of  the  treated  oats  as 
good  and  in  advance  of  those  not  treated.  No  effort  was  made  to  have 
especial  care  used  in. the  handling  of  the  treated  oats,  and  they  were 
usually  sown  in  a  strip  along  the  side  of  the  untreated  field. 

Just  before  harvest  the  fields  were  all  visited  and  the  per  cent,  of 
smut  in  the  treated  and  untreated  oats  determined.  The  details  of  the 
experiment  are  given  in  Table  13.  In  only  two  of  the  treated  lots  of 
seed  was  the  per  cent,  of  smut  large  enough  to  be  determined,  being 
practically  nothing,  and  in  those  two  it  was  much  lower  than  in  the 
untreated.  On  the  other  hand  the  season  had  not  been  so  favorable  for 
the  development  of  smut,  as  the  check  fields  only  averaged  about  4%. 
Even  in  those  fields  where  it  was  least,  however,  one  could  easily  detect 
the  difference  between  the  treated  and  untreated  parts. 

At  each  of  the  localities  visited  one  lot  of  seed  was  treated  by 
sprinkling  with  formalin,  of  the  strength  of  one  pound  to  about  fifty 
gallons  of  water,  using  a  gallon  and  a  half  of  the  liquid  to  -the  bushel. 
This  treatment  did  not  prove  quite  so  effective  as  the  hot  water  treat- 
ment, probably  because  the  solution  used  was  hardly  strong  enough. 

Another  point  it  was  desired  to  bring  out  in  these  experiments  was 
whether  the  crop  resulting  the  second  year  from  treated  seed  would  be 
fairly  free  from  smut,  providing  no  special  care  were  taken  in  the  hand- 
ling, planting,  and  threshing  of  the  crop  from  treated  seed.  The  data 
obtained  on  this  point  are  not  so  extensive  as  desired,  but  those  report- 
ing stated  that  there  was  less  smut  in  the  crop  which  had  received  seed 
treatment  the  year  before,  than  in  that  which  had  not.  These  results  are 
promising  for  this  procedure  when  it  is  remembered  that  the  treated 
seed  was  nearly  always  planted  side  by  side  with  the  untreated  and  so 
was  sure  to  have  at  least  some  smut  blown  on  the  seed  in  the  field.  If 
one  wishes  to  try  limited  seed  treatment  to  obtain  clean  seed  for  another 
year's  use,  there  are  two  precautions  that  need  to  be  taken  that  were  not 
in  these  cases.  First,  the  treated  seed  must  be  planted  by  itself,  and, 
second,  no  other  oats  should  be  mixed  in  the  handling,  etc.,  with  those 
of  this  crop.  By  watching  his  oats  and  applying  such  treatment  when 
needed,  a  farmer  should  suffer  very  little  from  this  foe  and  at  the  same 
time  be  at  no  very  great  trouble  in  keeping  it  down. 


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SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


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316  BULLETIN  NO.   57.  \_Mar  ch> 

Conclusions  from  Prevention  Experiments.  From  the  results  of  the 
various  experiments  conducted,  the  following  conclusions  are  made: 
i.  Seed  treatment  can  be  made  very  effective  for  prevention  of  oat 
smuts.  2.  Of  all' the  means  tried,  hot  water  and  formalin  proved  the 
most  efficient.  3.  The  sprinkling  method  with  formalin,  strength  ilb. 
to  40  or  50  gallons  water,  was  by  far  the  simplest  of  these  two,  and  as. 
such  has  much  to  recommend  its  general  use.  4.  The  experiments  con- 
ducted with  stronger  solutions  of  formalin  and  less  amounts  applied, 
leaving  the  fumes  to  act,  suggest  possibilities  in  this  direction  of  import- 
ance, since  in  this  way  is  eliminated  the  problem  of  drying  the  seed  or 
the  difficulty  of  handling  it  wet  if  sown  immediately.  5.  Limited  treat- 
ment of  only  enough  grain  to  obtain  clean  seed  for  another  year  is 
probably  the  best  procedure  in  most  cases,  especially  when  the  hot 
water  method  is  used.  6.  The  smut  that  produces  infection  is  chiefly 
that  which  is  blown  on  the  seed  in  the  field  and  so  unusual  precautions 
in  handling  treated  grain  are  hardly  necessary.  7.  But  treated  seed 
should  always  be  sown  by  itself  to  give  the  best  seed  for  another  year, 
and  in  harvesting  this  grain  care  should  be  taken  that  no  other  oats  be- 
come mixed  with  it. 

SMUT  OF  TALL  OAT  GRASS. 
Ustilago  perennans,  Rostr. 

This  is  a  smut  that  botanists  formerly  considered  identical  with 
those  on  oats,  as  it  has  much  the  same  general  appearance.  It  is  less 
destructive  to  the  flower  parts  than  the  loose  smut  of  oats,  being  more 
like  the  hidden  form  in  this  respect.  Usually  the  outer  glumes  are  not 
disturbed  and  even  the  destruction  of  the  parts  within  is  not  generally 
so  complete.  As  the  glumes  are  transparent  the  mass  of  spores,  which 
is  not  very  dusty,  shows  through,  having  a  dark  olive  brown  color. 

Under  the  microscope  the  spores  appear  about  like  those  of  the 
loose  smut,  being  somewhat  smaller,  5-7^,  in  diameter.  Brefeld*  states 
that  their  germination  is  exactly  like  that  of  oat  smuts  and  he  does  not 
consider  this  as  a  distinct  species. 

The  mycelium,  like  its  host,  is  perennial  so  that  the  smut  will 
appear  year  after  year,  and  because  of  this  the  culms  from  a  smutted 
plant  are  more  uniformly  smutted  than  in  those  cases  where  the  host  is 
an  annual.  In  one  case  a  count  was  made  of  fifty  smutted  culms,  all 
apparently  from  the  same  plant.  Very  few  panicles  appear  the  first 

*Bre£eld  classifies  the  smuts  that  were  formerly  placed  under  Ustilago  sege- 
tum  as  follows:  The  loose  smut  of  wheat  and  barley  as  Ustilago  Hordei,  Brefeld; 
the  covered  smut  of  barley  as  Ustilago  fensenii,  Rostr.;  and  the  smut  on  oats  and 
oats  grass  as  Ustilago  Avencc  (Pers.)  Jens.,  the  last  two  species  being  closely  related. 
He  bases  his  classification  largely  on  the  results  of  cultures  of  spores  in  nutrient 
solutions. 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  317 

season,  but  the  smut  may  show  in  these.  The  second  year  the  plants 
normally  produce  their  flowers  and  from  this  on  the  smut  may  be  quite 
common  in  them. 

This  plant  is  not  often  raised  in  this  state  and  the  few  cases  where 
the  smut  has  been  found  have  been  in  the  Experiment  Station  plats. 
It  has  been  noticed  here  for  the  past  ten  years,  though  never  very 
abundant  till  in  1898.  As  the  host  is  raised  for  hay  and  as  the  smut 
always>occurs  in  the  panicles,  the  financial  loss  that  it  causes  is  not  so 
great  as  it  would  be  if  the  plant  were  a  cereal.  No  experiments  have 
been  conducted,  at  least  in  this  country,  for  prevention  through  seed 
treatment,  but  as  the  host  and  its  smut  are  closely  related  to  oats  and 
its  smuts,  it  seems  very  likely  that  such  treatment  would  prove  successful. 

LOOSE  AND  COVERED  SMUTS  OF  BARLEY. 
Ustilago  Hordei  (Pers.)  Kell.  &  Sw.      Ustilagonuda  (Jens.)  Kell.  &  Sw. 

Life  History.  Upon  barley  there  are  found  in  this  state  two  smuts 
that,  until  about  ten  years  ago  were  not  distinguished  as  distinct  species 
and  were  even  thought  to  be  identical  with  the  forms  on  oats,  etc.  The 
general  appearance  of  these  smuts  is  such  as  to  lead  one  to  suppose 
them  to  be  the  same,  since  they  both  occur  as  dusty  outbreaks  which 
more  or  less  completely  destroy  the  flower  parts.  They  are  known  as 
loose  and  covered  smut.  The  former  matures  its  spores,  which  are  of 
-a  dark  olive  brown,  to  the  destruction  of  the  flower  parts  of  an  infected 
spike,  and  with  time  these  are  dissipated  until  nothing  remains  but  the 
•naked  rachis.  The  latter,  whose  spores  are  of  a  purplish  black  color, 
has  these  outbreaks  protected  by  a  membrane  which  thus  more  perma- 
nently holds  the  spores  together. 

Under  the  microscope  the  spores  of  both  forms  are  somewhat 
lighter  colored  on  one  side,  but  differ  by  the  covered  smut  having  sub- 
spherical,  dark,  smooth  spores,  while  the  other  has  oval  to  sub-spherical, 
lighter,  minutely  echinulate  ones.  The  spores  of  the  covered  smut  are 
said  in  germination  to  produce  an  abundance  of  sporidia  much  after 
the  manner  of  oat  smuts,  while  those  of  the  loose  smut  produce  only 
infection  threads,  thus  closely  allying  itself  to  the  loose  smut  of  wheat. 
Both  forms  gain  entrance  into  the  host  through  the  young  tissues  of  the 
germinating  seed,  the  mycelium  following  the  upward  growth  and  pro- 
ducing its  spores  in  the  spikes  at  the  time  the  flower  parts  are  develop- 
ing. Jensen  has  shown  that  it  is  the  spores  that  fall  down  between  the 
•open  glumes  in  the  field  that  are  the  chief  source  of  infection,  and  it  is 
very  likely  that  with  the  loose  smut  these  spores  germinate  at  that  time 
and  infect  the  seed  coats  with  a  hibernating  mycelium  that  the  ensuing 
year  gains  entrance  to  the  seedling.  This  would  explain  the  failure  of 
'the  ordinary  methods  of  seed  treatment  to  prevent  the  smut. 


318  BULLETIN  NO.    57.  [March, 

Damage.  These  smuts  cause  comparatively  little  financial  loss  in 
this  state,  primarily  because  the  barley  crop  is  not  very  large,  its  value 
for  1897  being  estimated  at  but  a  little  over  $130,000.  The  collections 
of  these  smuts,  because  of  this  infrequency  with  which  barley  is  grown, 
have  been  comparatively  few,  chiefly  those  made  from  barley  grown 
on  the  Experiment  Station  grounds.  No  complaint  has  been  received 
from  farmers  concerning  them.  It  would  seem  from  the  few  fields 
examined  that  they  have  been  even  less  abundant  here  than  the  loose 
smut  of  wheat.  However,  they  are  quite  common  in  those  countries 
where  barley  is  extensively  grown  and  seem  to  be  nearly  as  injurious 
there  as  the  smuts  of  oats. 

Prevention.  Very  little  has  been  done  in  this  country  looking 
toward  the  prevention  of  these  smuts.  Jensen,  of  Denmark,  however, 
has  experimented  along  this  line  and  has  found  that  the  covered  smut 
could  be  prevented  by  the  ordinary  hot  water  treatment  of  seed,  but 
that  the  loose  smut  was  not  prevented  by  such  treatment.  He  found, 
though,  that  it  could  be  controlled  by  a  modification  of  this  method,  a 
more  severe  treatment  in  which  the  seed  is  first  soaked  for  four  hours  in 
cold  water,  then  allowed  to  stand  damp  four  more  in  sacks,  after  which 
a  hot  water  treatment  at  i26°-8°  F.  is  given  for  five  minutes.  The 
necessity  for  this  difference  in  treatment  to  prevent  the  two  forms  is 
probably  caused  by  the  development  of  the  hibernating  mycelium  in  the 
loose  smut,  the  destruction  of  which  is  accomplished  only  by  the  severer 
treatment. 

LOOSE  SMUT  OF  WHEAT. 
Ustilago  Tritici  (Pers. )  Jens. 

Life  History.  This  is  another  smut  until  recently  classed  with  the 
preceding  forms,  because  of  the  general  similarity  in  appearance  of  the 
outbreaks  and  spores.  The  affected  spikes  have  their  flower  parts 
changed  into  a  dusty,  dark  olive  brown  mass  very  much  like  loose  smut 
of  barley.  Usually  the  destruction  is  so  complete  that  there  eventually 
remains  only  the  naked  rachis.  • 

The  appearance  and  germination  of  the  spores,  and  in  fact  the  whole 
life  history  indicate  its  close  relationship  to  this  smut  of  barley.  It  also 
seems  to  be  true  that  infection  first  really  takes  place  in  the  field  by  the 
development  of  a  temporary  mycelium  in  the  seed  coats.*  This  will 
explain  several  points  peculiar  about  the  fungus;  namely,  its  ability  to  get 
along  without  sporidia,  low  percentage  of  germination  of  spores,  the 
few  cases  of  infection  (one  per  cent. )  that  Jensen  obtained  when  mixing 

*Massee  states  that  frequently  with  Ustilago  Vaillantii  the  mycelium  penetrates 
the  coats  of  seeds  not  destroyed  by  smut,  and  the  next  year  these  develop  smutty 
plants.  Maddox  inoculated  wheat  spikes  with  smut  one  year  without  the  grain  be- 
coming smutty,  and  from  this  seed  produced  smutty  plants  the  next  year. 


igoo.~\  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  319 

smut  with  mature  seed,  and  the  failure  of  the  ordinary  methods  of  seed 
treatment.  The  soft  young  wheat  kernels  at  the  time  the  smut  first 
appears  seem  also  to  offer  a  good  chance  for  such  infection. 

Damage.  As  with  oats  the  damage  consists  in  the  destruction  of 
the  grain  and  the  partial  stunting  of  the  culms.  Wheat  smut  does  not 
seem  quite  so  abundant  in  this  state  as  oat  smut,  though  it  is  more  or 
less  common  in  most  fields.  Neither  does  wheat  occupy  quite  so  promi- 
nent a  feature  in  our  agriculture,  especially  of  late  years.  For  these  iwo 
reasons  the  financial  loss  is  not  so  great  as  from  the  oat  smuts.  It  is 
serious  enough,  however,  to  demand  attention. 

Very  few  counts  to  determine  the  per  cent,  of  smut  in  wheat  fields 
have  been  made,  as  little  wheat  is  raised  in  the  vicinity  of  the  Experi- 
ment Station.  In  1892  counts  made  in  several  plats  of  one  variety  grown 
at  the  Station  showed  an  average  of  5%, while  another  variety  was  esti- 
mated to  have  less  than  yz  %.  Counts  made  in  two  fields  in  the  vicinity 
showed  a  presence  of  5%  in  one  case  and  15%  in  the  other,  this  latter 
having  been  selected  as  one  containing  an  unusually  large  amount. 

Prevention.  No  experiments  of  value  for  prevention  have  been 
tried  here  and  those  conducted  elsewhere  have  generally  given  negative 
results.  The  experiments  at  the  Ohio  Experiment  Station  with  the  modi- 
fied hot  water  treatment,  however,  show  that  seed  treatment  is  effective 
when  made  severe  enough  to  injure,  in  part,  the  germination  of  the 
seed.  The  treatment  recommended  is  to  soak  the  seed  four  hours  in 
cold  water,  then  to  let  it  stand  four  more  wet  in  the  sacks,  after  which  to 
give  hot  water  treatment  of  133°  F.  for  five  minutes.  As  this  kills  part  of 
the  seed,  one  and  a  half  times  the  usual  amount  should  be  sown  per 
acre.  On  account  of  the  severity  of  the  treatment,  it  would  seem  ad- 
visable to  treat  only  enough  to  obtain  clean  seed  for  another  year's  use. 

STINKING  SMUT  OF  WHEAT.* 

Tilletia  foetens  (B.  &  C.)  Schroet. 

Life  History.  This  smut  merely  transforms  the  grain  into  a  slightly 
enlarged  smutted  kernel,  leaving  the  glumes  entirely  free,  so  that  an  in- 
fected spike  has  much  the  same  appearance  as  a  free  one.  For  this 
reason  the  smut  is  easily  overlooked  in  the  field.  It  can  sometimes  be 
detected  by  the  color  of  the  infected  spike  and  very  often  by  the  pres- 
ence of  the  smut  eating  beetle.  Its  odor  is  quite  characteristic,  as  it  is 
very  fetid,  and  is  retained  for  years  by  the  smutted  kernels. 

*There  is  another  stinking  smut,  Tilletia  Tritici  (Bjerk.)  Wint.  that  has  been 
occasionally  reported  in  this  country.  So  far  this  has  not  been  found  in  this  state, 
though  it  very  likely  occurs  here,  as  specimens  have  been  sent  in  for  determination 
from  adjacent  states.  The  two  can  be  told  apart  only  on  microscopic  examination, 
7.  Tritici  having  prominently  reticulated  spores,  while  those  of  T.  foetens  are 
smooth.  They  seem  to  have  much  the  same  life  history. 


320  BULLETIN  NO.   57.  [March, 

This  smut  is  entirely  different,  botanically,  from  any  of  the  preced- 
ing species.  The  spores  are  comparatively  quite  large,  mostly  18-2 4u 
in  diameter,  are  smooth  and  chiefly  sub-spherical  or  spherical  in  shape. 
In  germination  they  send  out  a  pro-mycelium  two  to  several  times  the 
length  of  the  spore,  upon  the  end  of  which  are  produced  a  number  of 
long,  slender  sporidia  tapering  toward  the  free  end.  These  soon  assume 
a  more  or  less  bow  shape  and  from  the  center  of  the  convex  side  give 
rise  to  a  short  protuberance,  which  if  rightly  situated  coalesces  with  a 
similar  protuberance  from  an  adjacent  sporidium.  There  are  now  de- 
veloped either  infection  threads  or  secondary  sporidia  from  the  result- 
ing outgrowths.  The  secondary  sporidia  may  in  time  produce  infection 
threads.  By  these  the  fungus  gains  entrance  into  the  germinating  seed 
and  through  the  developed  mycelium  follows  the  upward  growth  of  the 
plant,  eventually  forming  its  spores  in  the  seed  producing  parts. 

Damage.  This  smut  is  one  of  the  best  known,  and,  in  large  wheat 
districts  of  this  and  the  old  world,  is  one  of  the  most  destructive  smuts. 
Although  it  has  probably  long  occurred  in  this  state,  the  first  col  ec- 
tions  in  the  herbarium  were  made  in  1892  from  the  Experiment  Station 
plats.  A  careful  examination  of  these  the  year  or  two  previous  had 
failed  to  show  the  presence  of  this  fungus,  but  in  this  year  it  was  found  in 
small  amounts  in  several  plats,  and  in  one  plat  counts  showed  4%  present. 
The  same  year  N.  W.  Graham  complained  of  its  being  very  bad  in  the 
neighborhood  of  Carbondale.  He  wrote:  "For  several  years  past  we 
have  had  almost  no  smut  in  this  county,  but  this  year  it  is  worse  than  I 
ever  knew  it."  He  sent  several  thousand  infested  spikes  gathered  from 
a  single  acre  of  land.  Inquiries  have  shown  that  it  has  occurred  in 
various  parts  of  the  state,  but  at  present  does  not  seem  to  be  attracting 
much  attention,  probably  because  wheat  is  not  now  extensively  raised 
except  in  southern  Illinois.  It  is  a  fungus,  however,  that  undoubtedly 
in  some  years  and  in  certain  fields  causes  considerable  loss.  The  fungus 
is  also  objectionable  because  in  flour  made  from  very  smutty  wheat  more 
or  less  spores  get  into  it,  making  it  of  an  inferior  grade. 

Prevention.  In  the  fall  of  1895  the  Station  made  the  only  experi- 
ment it  has  conducted  for  the  prevention  of  this  smut.  Very  smutty 
seed  was  mixed  with  an  additional  amount  of  smut  and  then  half  of  it 
was  treated  with  hot  water  at  i32°-4°F.  for  fifteen  minutes,  after  which 
both  parts  were  planted  in  small  plats  side  by  side.  Much  of  the  wheat 
in  both  plats  was  winter  killed,  but  all  of  the  spikes  in  both  plats  were 
counted,  showing  the  treated  plat  entirely  free  from  smut,  while  the 
check  plat  contained  3%.  Extensive  experiments  have  been  conducted 
by  the  Experiment  Stations  of  Kansas,  Indiana,  and  North  Dakota  and 
their  results  show  that  this  smut  can  be  prevented  by  the  hot  water  treat- 
ment. The  copper  sulfate,  or  blue  stone  treatment,  has  long  been  used, 
though  frequently  it  acts  severely  on  the  seed.  The  North  Dakota 


SMUTS    OF    ILLINOIS'    AGRICULTURAL    PLANTS.  32! 

Station  has  experimented  more  than  any  of  our  other  stations  with 
different  methods  of  preventing  this  smut,  and  it  now  recommends  the 
thorough  sprinkling  of  the  grain  with  formalin  (i  Ib.  to  50  gallons  water) 
and  leaving  in  piles  over  night. 

SMUT  OF  INDIAN  CORN  AND  TEOSINTE.* 
Ustilago  Zece  (Beckm.)  Unger. 

Life  History.  Corn  smut  apparently  breaks  out  on  any  part  of 
the  plant  except  the  silks  of  the  ears  and  the  underground  roots,  though 
its  presence  on  the  internodes-is  generally  limited  to  its  spreading  from 
an  infection  at  the  node.  The  attack  maybe  quite  general  though 
never  so  abundant  that  the  whole  plant  becomes  distorted,  or  it  may 
be  limited  to  a  single  small  outbreak.  These  smut  balls  vary  from  quite 
prominent  distortions  several  inches  in  diameter  to  those  only  the 
fraction  of  an  inch,  the  largest  generally  appearing  in  the  ears  and  the 
smallest  in  the  leaves  and  tassels.  The  smut  does  not  make  its  appear- 
ance until  the  plants  have  become  rather  large,  the  first  outbreaks  show- 
ing usually  on  the  leaves.  The  affected  parts  often  assume  quite 
abnormal  shapes,  as  for  instance  the  filaments  may  become  greatly 
enlarged  beyond  the  size  of  the  anther,  this  remaining  free  from  the 
fungus,  or  the  individual  kernels  of  the  ear  may  become  greatly  dis- 
tended. When  the  smut-ball  first  appears  it  is  protected  by  a  whitish 
membrane  within  which  is  a  moist  mass  of  half  ripe  spores,  fungous 
threads,  and  some  planj  tissues;  but  as  it  matures  the  whole  is  changed 
into  a  dusty  mass  of  spores  and  becomes  more  or  less  dissipated  in 
time. 

The  spores  are  of  rather  large  size,  chiefly  8-i$u,  and  mostly  sub- 
spherical  in  shape,  though  occasionally,  especially  through  pressure, 
they  assume  a  variety  of  shapes.  They  are  of  a  black  brown  color  in 
mass.  Their  outer  cell  wall  is  prominently  and  abundantly  provided 
with  echinulations.  They  germinate-  readily  in  nutrient  solutions  at 
almost  any  time  of  the  year.  In  water,  however,  this  germination  can 
not  so  surely  be  depended  on,  though  sometimes  beginning  before  the 
end  of  twenty-four  hours.  A  rather  elongated  four-celled  pro-mycelium 
is  developed  which  may  run  out  into  a  quite  elongated  thread.  Occa- 
sionally the  pro-mycelium  becomes  branched,  especially  at  the  base. 
Terminal  and  lateral  sporidia  are  formed;  but  if  excluded  from  air  these 
generally  soon  fall  off  and  are  not  produced  very  abundantly.  When 
the  germ  threads  reach  the  air,  however,  the  sporidia  are  produced  very 

*  The  smuts  occurring  on  these  two  hosts  are  undoubtedly  the  same,  as  is 
shown  by  the  character  of  the  outbreaks  and  the  appearance  and  germination  of  the 
spores.  Teosinte  is  rarely  grown  here  except  as  a  curiosity  and  the  only  collections 
of  smut  on  it  have  been  at  the  Exp.  Stat.  The  following  treatment  relates  only  to 
the  smut  as  it  occurs  on  corn. 


322  BULLETIN  NO.   57.  [March, 

abundantly  in  simple  or  branched  chains  that  remain  attached  to  the 
spore.  Often  the  pro-mycelium  becomes  detached  near  its  base,  and 
continues  its  development  alone.  The  sporidia  are  somewhat  fusiform 
bodies  that  vary  considerably  in  size,  very  often  it  being  difficult  to  tell 
them  from  the  detached  pro-mycelia.  In  germination  they  send  out 
small  bent  infection  threads.  The  germination  of  the  spores  is  much 
the  same  in  a  nutrient  solution,  of  course  being  much  more  luxuriant 
and  abundant.  The  sporidia  in  Cohn's  modified  solution  are  pro- 
duced in  such  abundance  by  budding  as  to  form  a  conspicuous  white 
crust  or  sediment.  On  the  whole  corn  smut  is  more  luxuriant  in  the 
production  of  sporidia  than  any  of  the  other  smuts  described  here. 

The  reason  for  this  abundance^  of  sporidia  and  their  preference  for 
aerial  formation  is  explained  when  the  manner  by  which  they  infect 
their  host  is  considered.  This  takes  place  through  the  very  young  parts 
of  the  plant  above  ground,  and  no£,  at  least  to  any  extent  in  nature, 
through  the  germinating  seed,  as  is  the  case  with  our  other  smuts. 
This  manner  of  infection  to  be  successful  requires  an  abundance  of  in- 
fecting bodies  and  the  aid  of  the  wind.  As  the  exposed  parts  of  the 
plant  are  too  old  for  infection  there  can  be  little  doubt  that  water  in 
the  shape  of  rain  and  dew  is  a  prominent  factor  in  carrying  down  the 
germs  that  are  blown  on  the  plant  to  points  young  enough  for  infection. 
After  gaining  entrance  the  fungus  has  to  contend  with  the  rapidly  ma- 
turing tissues,  and  so  it  becomes  localized  and  rapidly  passes  through 
the  mycelium  to  the  spore  stage.  The  time  tak^en  for  this  most  likely 
varies  somewhat  with  the  organ  infected,  probably  extending  from  about 
ten  days  to  three  weeks.  In  the  leaves  this  maturing  of  tissues  is  the 
most  rapid  and,  so  while  they  are  the  most  exposed  parts  of  the  plant, 
they  usually  show  the  fewest  outbreaks.  Other  parts,  as  the  ears,  that 
are  slower  in  development  and  thus  more  open  to  attack,  are  provided 
with  greater  protection  against  the  presence  of  the  germs.  Of  all  the 
parts  the  axillary  growths,  found  wrapped  up  by  the  bases  of  the  leaves, 
are  the  most  susceptible  to  infection,  probably  because  they  remain  so 
long  in  their  nascent  condition  and  at  most  develop  only  weak  tissues. 
They  are  also  situated  very  favorably  for  having  germs  washed  down  on 
them.  An  inspection  of  the  tables  shows  that  most  of  the  smutty  out- 
breaks occurred  at  these  lower  nodes.  When  the  plants  are  young, 
either  from  more  rapid  development  of  the  parts  or  their  greater  protec- 
tion, they  seem  more  exempt  from  infection  than  at  the  time  they  have 
about  made  their  full  growth,  just  before  the  tassels  are  protruded. 

Damage.  As  the  grain  is  the  chief  object  for  which  corn  is  grown, 
one  can  properly  measure  the  injury  of  the  smut  by  its  action  on  this 
part  alone.  This  injury  manifests  itself  both  directly  and  indirectly. 
The  smut,  for  instance,  may  break  out  in  the  ear  itself  totally  destroying 
it.  The  effect  is  then  direct  and  easy  of  determination.  The  injury  is 


i  goo.  ] 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


323 


still  direct  when  the  ear  is  only  partially  destroyed,  but  the  estimation 
of  damage  is  more  difficult.  This,  however,  is  not  the  greatest  diffi- 
culty in  the  way  of  determining  the  damage  inflicted.  A  glance  at  the 
tables  given  shows  that  the  outbreaks  in  the  ears  are  few  compared  with 
the  total  number.  There  must  be  determined  the  indirect  effect  that 
such  adjacent  infections  have  on  the  number  and  size  of  ears  produced. 
Such  complications  make  it  impossible  to  determine  the  damage  after 
the  manner  employed  with  oats  smut,  by  determination  of  percentage  of 
smutty  stalks. 

The  proper  way  for  estimating  this  loss  is  to  determine  the  per 
cent,  of  smutted  stalks  in  a  field  and  then  from  a  representative  and  suf- 
ficiently large  area  to  determine  separately  the  yield  from  the  smutty 
and  the  free  stalks.  Hitchcock,  of  Kansas,  found  that  the  difference  in 
yield,  in  one  very  smutty  field,  between  the  free  and  smutty  stalks  was 
one-third.  This,  however,  is  a  difference  that  is  variable  and  may  not 
correspond  with  the  amount  of  smut,  as  a  field  may  have  considerable 
and  still  be  little  damaged  by  it.  This  is  shown  in  the  case  reported  in 
Table  17,  where  an  effort  was  also  made  to  determine  the  difference  in 
yield  between  the  smutty  and  free  stalks.  In  this  case  the  difference, 
8%,  which  was  determined  by  number  of  ears  rather  than  by  weight, 
showed  but  little  in  favor  of  the  free  stalks.  As  this  plat  had  only  20% 
of  the  stalks  smutty,  the  total  loss  did  not  exceed  2%.  That  this  was 
so  low  was  due  to  the  fact  that  while  there  was  a  large  number  of  smutty 
outbreaks  very  few  of  them  occurred  on  the  ears.  The  data  obtained  is 
given  in  Table  14.  That  this  loss  was  largely  confined  to  the  stalks  that 

TABLE  14.     EFFECT  OF  CORN  SMUT  ON  NUMBER  AND  SIZE  OF  EARS. 


H 
o 

0 

C/3 

s. 

|_ 

Large 
ears 

Medium 
ears. 

Small 
ears. 

Ears. 

Condition  of  stalks. 

en 

"1    ^ 
en   3. 

O 

e 

c 

8s 

a 

8s 

Z 
c 

-M    50 

8s 

H 

8s 

55 

a- 

B 

en   o 

B 

en   o 

B 

en   o 

o 

en   o 

en 

en 

o 

p 

CT 

p  *< 

or 

S.'o 

P  »Q 

• 

JO  _j 

5T  <* 

y?  n 

?r  en 

X"  CB 

en   -i 

en  1-1 

en   ^ 

en   •-! 

Free  

247 

80 

53 

21 

S2 

21 

87 

35 

52 

21 

191 

77 

Smutty  

60 

2O 

12 

20 

21 

25 

5 

9 

43 

TABLE  15.     AMOUNT  OF  SMUT  ON  CORN  AS  AFFECTING  NUMBER  AND  SIZE  OF  EARS. 


Condition  of  stalks. 

No. 
stalks 

% 
stalks 

Number  of  ears. 

Ratio 
per 
100  stalks 

Large 

Medium 

Small 

Total 

Badly  smutted  

6 
15 
39 

10 

25 
65 

o 

2 

ii 

0 

8 
17 

i 

2 
2 

i 

12 
30 

16 

80 
77 

Moderately  smutted  

Little  smutted  

were  badly  smutted,  though  it  apparently  affected  the  size  of  the  ears  in 
the  moderately  smutted  plants,  is  shown  by  Table  15,  in  which  is  given 


324  BULLETIN    NO.     57.  \_Mcirch, 

the  number  and  character  of  the  ears  on  the  stalks  badly,  moderately, 
and  but  little  smutted. 

On  the  other  hand  the  loss  that  occurred  in  the  plat  reported  in 
Table  16  was  very  great,  as  here  many  of  the  smutty  outbreaks  occurred 
in  the  ears.  On  the  whole,  however,  we  are  inclined  to  believe  that  the 
loss  caused  by  this  fungus  is  generally  over-estimated.  From  our  exam- 
ination of  fields  we  should  judge  that  it  usually  ran  from  ^%  to  5%, 
and  that  the  loss  for  the  whole  state,  year  after  year,  is  probably  less 
than  2%.  That  this  is  so  small  is  fortunate,  since  corn  is  by  far  our 
most  valuable  crop,  that  of  1898  being  estimated  at  $50,000,000. 

EXPERIMENTS. 

Conditions,  etc.  Field  experiments  with  corn  smut  were  carried  on 
from  1895  to  1898.  Data  concerning  conditions  and  results  of  these 
experiments  are  given  in  Tables  16-24.  Spores  were  used  as  the  infect- 
ing agent,  and  unless  otherwise  stated  were  from  the  same  host  (sweet 
corn  Smut  with  sweet  corn,  etc.),  and  were  taken  from  the  previous 
year's  crop.  It  was  tried  to  make  the  conditions  exactly  the  same  for 
all  plats  of  a  given  table,  except  those  mentioned  under  heading  of 
treatment.  The  examinations  of  the  plats  were  made  after  the  smut 
ceased  to  appear,  unless  it  was  in  those  of  Table  16,  where  the  first  plats 
were  probably  examined  a  little  too  soon  and,  as  it  took  a  week  between 
examination  of  first  and  last  plats,  this  may  account  in  part  for  the  higher 
showing  made  in  the  later  ones.  The  experiments  were  begun  under 
the  impression  that  the  chief  manner  of  infection  was  through  the  ger- 
minating seed  either  from  attached  germs  or  those  in  the  ground,  and 
so  the  experiments  for  the  first  two  years  were  largely  along  lines  thus 
suggested. 

To  judge  correctly  of  the  results  of  these  experiments  is  more  diffi- 
cult than  with  related  experiments  with  oats  smut,  since  with  the  latter 
conditions  can  be  made  such  that  the  checks  are  free  from  smut.  With 
corn  there  is  a  variable  amount  of  smut  present  in  field  experiments, 
no  matter  what  the  treatment.  This  makes  it  difficult  to  determine  what 
is  due  to  the  specific  treatment  unless  it  is  very  marked  or  localized. 
The  plats  receiving  no  treatment  have  been  used  as  checks,  and  the  per- 
centage of  smutty  stalks  has  been  taken  as  a  standard  of  comparison. 
Since  infection  is  local,  however,  two  distinct  outbreaks  on  different 
parts  of  the  same  stalk  would  mean  as  much  as  a  single  outbreak  on  each 
of  two  stalks,  though  not  showing  the  same  in  the  percentages.  This 
condition  is  taken  into  consideration  by  the  determination  of  total  dis- 
tinct outbreaks  in  each  plat  and  their  enumeration  in  ratios  of  so  many 
per  hundred  stalks.  These  ratios,  however,  generally  show  about  the 
same  relationship  between  different  plats  as  do  the  percentages.  As  the 
position  of  the  smutty  outbreak  may  have  some  relation  to  the  manner 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  325 

of  attempted  infection,  there  is  given  in  each  case  the  number  of  out- 
breaks on  the  different  parts  of  the  plant.  On  account  of  the  differences 
that  might  be  made  by  season,  land,  etc.,  one  can  compare  with  each 
other  only  treatments  in  the  same  table,  though  the  general  idea  of  a 
treatment  may  be  gained  from  its  results  from  year  to  year.  In  order 
to  determine  the  variation  that  might  occur  within  the  same  plat,  so  as 
to  know  more  fully  how  to  judge  of  variations  between  plats,  these  ob- 
servations were  made  for  each  row,  though  in  the  tables  only  the  totals 
for  the  plat  are  given.  This  variation  within  plats  was  sufficient  to  make 
it  necessary  to  neglect  all  but  the  prominent  variations  that  occurred 
between  plats.  Those  that  show  smut  evidently  produced  by  the  treat- 
ment are  marked  with  bold  faced  type. 

One  of  the  most  prominent  things  that  suggests  itself  from  a  review 
of  these  tables  was  the  common  failure  to  produce  any  great  variation  in 
amount  of  smut  due  to  the  treatment  given.  Possibly  in  some  cases  this 
may  have  been  due  to  the  use  of  spores  and  might  have  been  different 
had  sporidia  been  used,  as  was  done  by  Brefeld  in  his  experiments,  since 
corn  smut  spores  do  not  always  germinate  in  water.  However  in  most 
of  the  cases  failure  of  infection  can  not  be  attributed  to  the  use  of  spores 
but  to  the  fact  that  it  does  not  commonly  take  place  in  nature  under 
such  conditions.  For  convenience  the  discussion  of  the  results  and  ob- 
servations made  in  their  collection  will  be  given  under  the  following 
heads  :  Prevention,  Infection,  Relation  to  Land,  etc. 

Prevention.  The  experiments  show  emphatically  that  this  smut 
can  not  be  prevented  by  seed  treatment.  This  is  in  accordance  with 
the  results  of  experiments  that  have  been  reported  by  others.  The  ex- 
periments also  show  that  seed  treatment  has  no  influence  in  reducing 
the  amount  of  smut.  In  the  nine  different  comparable  cases  in  the  fol- 
lowing tables  of  ordinary  seed  treated  and  untreated  the  average  num- 
ber of  smutty  outbreaks  in  the  two  cases  is  almost  exactly  the  same, 
while  in  the  individual  cases  sometimes  the  treated  and  sometimes  the 
untreated  plats  gave  a  little  higher  number.  The  same  is  true  of  the 
cases  where  the  seed  was  mixed  with  smut  and  then  part  of  it  treated. 

The  experiments  in  1895  in  treating  the  soil  with  chemicals  showed 
no  evidence  that  this  was  effective  in  reducing  the  amount  of  smut, 
though  it  did  injure  the  germination  of  the  seed  in  one  case.  The  spray- 
ing experiments  with  Bordeaux  mixture,  while  not  very  extensive,  did 
not  show  any  results,  unless  it  was  in  case  of  plat  4,  Table  18.  Noth- 
ing can  be  expected  of  this  treatment,  however,  as  it  is  impracticable. 
Neither  does  the  spray  readily  adhere  to  the  leaves,  and  as  it  does  not 
reach  the  parts  through  which  infection  takes  place  it  can  act  only  in  a 
general  way. 

Selection  of  land  is  not  a  means  for  prevention,  as  smut  appeared 
in  all  of  the  different  plats,  though  from  the  observations  made  in  this 


326 


BULLETIN    NO.     57. 


[March, 


Average  outbreaks  per  hundred  stalks  for  all  plats  except 
face  type)  influenced  bv  treatment.  .  .  .43. 

those  (in  bold 

13 

Rateof  out- 
breaks per 
100  stalks. 

O  co        r 

«»rot^            CO             OO         ro      p^   pi         t^vo 

OO         t-^        CT>vO 
•>*•       m       ro  m 

ro 

M 

In  suckers 

MOOO                     O               OO               OO 

O 

0 

M 

O 

o 

O 

In  husks. 

0000                     0                Hi 

O               O          " 

0 

H 

M 

HI 

ro 

O 

In  tassels. 

M      HI               H              O                                 O                       O 

o           o       o 

0 

0 

VO 

O 

M 

HI 

In  matur- 
able  ears. 

vo   in        t^*        VN                    ON             C 

VO     t"*"             C**             HI                                 Ml/* 

O               PI        vo 

CO 

in       PJ 

HI 

vo 

ro 

S 

CO 

In  leaves. 

M      M               0              0                                 0 

0 

H             H 

PI 

0 

0 

0 

PI 

o 

In  upper 
nodes. 

cO  Q\        CO          O                       w 

ro        M               ^*-       00        vo 

t 

C 

o 

C 

VD 

HI 

o 

In  lower 
nodes. 

0      HI 

m  w 

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mm                 o             ro       r-»            o       oo 
N         PI                     ro             vo         ro              ON       CC 

C 
PI 

*  "     *        Q 

ro        ON        O 

H              HI              HI 

ON 
PI 

VO 
ro 

Smutty 
outbreaks. 

pi   C1"-        HI   Tt-        ro             O              t^ 
PI    O           HI    N           M                  m                 w 
MNP)                                                                       H 

•CO         IN    t*<-         T: 

IT)         ^     CO           l> 

CO        OO        VO         C-»  ON 
M         ON        ro        Tf  M 
ro        w         ro        M    in 

m 

%  smutty 
stalks. 

in  r^      vo  ^t~       HI           vc 

VC 

^    5  S1     £ 

HI         ON       vo         f~  t^ 

N 

HI 

Smutty 
stalks. 

.  PI  m       o  oo        M             Tfr-            M 
o  "r      m  w        M            ro          oo 

MM             M 

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Treatment. 

Seed  treated  witljhot  water  (135°  Ffor  15  min.)  
Seed  mixed  with  smut.  . 

Seed  mixed  with  smut,  then  hot  water  treatment  (135°  F 
for  is  min.}  .  . 

Hot  water  treatment  (135°  F  for  15  min.)  Sweet  corn 
smut  placed  on  young  plants  before  they  appeared  above 
ground.  Last  %  not  treated  with  smut  
Hot  water  treatment(i35°F  for  15  min.)  Sweet  corn  smut 
placed  on  underground  parts  just  after  plants  appeared 
above  eround.  . 

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placed  in  water  on 
above  eround.  . 

Hot  water  treatment  ( 
When  plants  were  in 
mutilated  plants  badlj 
ing  off  different  parts 
Seed  treated  with  hot  wa 
Seed  treated  with  hot  wa 
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IQOO.~\  SMUTS    OF    ILLINOIS'    AGRICULTURAL    PLANTS.  327 

connection  there  is  no  doubt  but  that  this  may  have  some  influence  in 
determining  the  amount  of  smut.  It  would  seem,  'as  claimed  by  Brefeld, 
that  the  presence  of  manure  is  an  important  factor  in  this  case  and  also 
whether  there  had  been  a  very  smutty  crop  on  the  land  the  year  before. 

There  is  no  doubt  but  that  different  varieties  vary  somewhat  in 
their  resistance  to  infection.  Such  difference  is  undoubtedly  due  to  the 
manner  of  maturing  their  tissues,  closeness  with  which  parts  envelope 
young  tissue,  rapidity  of  growth,  etc.  Sweet  corn  is  said  to  smut  easier 
than  field,  and  it  was  noticed  that  those  varieties  of  field  corn  that  were 
slow  in  maturing  or  of  rank  growth,  as  Giant  Mexican,  were  most 
inclined  to  become  smutty. 

Infection.  The  sum  total  of  all  of  the  experiments  to  infect  the  plants 
before  they  appeared  above  ground  *vas  of  a  negative  character.  Mix- 
ing spores  with  the  seed  was  just  as  apt  to  give  a  crop  as  free  from  smut 
as  to  use  ordinary  or  even  treated  seed.  These  failures  to  influence 
amount  of  smut  through  seed  treatment  can  not  be  attributed  to  lack  of 
germinating  spores,  for  in  1897  where  smut  was  mixed  with  manure  and 
placed  around  seeds  there  was  still  no  evident  increase.  The  experi- 
ments in  plats  12-13,  Table  24,  indicate  that  infection  does  not  occur 
by  means  of  a  latent  mycelium  that  might  be  formed  in  young  seed  de- 
veloped in  contact  with  smutty  outgrowths  on  the  same  ear. 

The  spraying  of  spores  on  the  young  parts  of  the  plant  during  dif- 
ferent stages  of  its  growth  gave  no  very  evident  signs  that  the  per  cent, 
of  smut  was  thereby  increased,  though  in  the  case  of  plat  3,  Table  24, 
where  the  spores  were  in  manure  water  there  may  have  been  some  slight 
infection  from  this  treatment.  In  all  these  cases  the  spores  were  sprayed 
down  in  abundance  between  the  youngest  unfolded  leaves.  As  ex- 
plained before  this  failure  to  infect  may  have  been  partially  due  to  lack 
of  germination  of  spores. 

The  writer's  attention  having  been  called  to  the  fact  that  smut  was 
very  common  on  injured  places,  especially  noticeable  in  detasseled 
corn,  a  number  of  experiments  were  carried  on  in  this  direction.  In  the 
cases  where  the  plants  were  mutilated  young,  when  a  few  inches  to  two 
or  three  feet  high,  there  was  no  evidence  that  the  amount  of  smut  was 
increased.  Also  when  the  plants  were  mutilated  when  rather  mature 
(after  appearance  of  tassels  and  corn  changing  from  milk  to  dough 
stage)  the  results  were  negative.  In  the  cases  where  mutilation,  includ- 
ing usually  more  or  less  detasseling,  was  made  at  about  tne  time  for  ap- 
pearance of  the  tassels,  the  effect  was  usually  shown  by  the  increase  of 
smut  on  such  plants.  Thus  in  1895,  Table  16,  plat  8,  the  plants  were 
so  treated  after  determining  the  number  of  smutty  stalks  and  outbreaks 
and  when  it  was  thought  most  of  the  smut  had  made  its  appearance. 
Counts  made  on  the  same  row  two  weeks  later  showed  almost  double  the 
number  of  smutty  stalks  and  outbreaks.  All  of  these  could  not,  how- 


328 


BULLETIN    NO.     57. 


\March, 


Average  outbreaks,  etc.  26 

Rate  of  out- 

breaks per 
100  stalks. 

mm      oc  m 
M    N         N    ro 

In  suckers. 

MM           M    ro 

In  husks. 

MM               00 

In  tassels. 

Tf  O^        ro  N 
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In  maturable 

vo  m      o  M 

ears. 

In  leaves. 

ro  M        00    M 

MM               M     N 

In  upper 
nodes. 

N  VO          OO    tv 

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In  lower 
nodes. 

ro  m        O  CO 

Smutty 
outbreaks. 

M   cv        O   ro 
O^  in       &\  M 

•         M                       C< 

%  smutty 
stalks. 

N  vO         O^i  ro 

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stalks. 

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tv  o        vo   ro 

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mm       <s   T}- 

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IQOO.~\  SMUTS    OF    ILLINOIS'    AGRICULTURAL    PLANTS.  329 

ever,  be  attributed  to  the  mutilation,  as  counts  on  an  unmutilated  row 
also  showed  an  increase,  though  not  nearly  so  large.  Table  24,  where 
all  of  the  plats  were  detasseled  to  prevent  interfering  with  another  corn 
experiment,  gives  the  most  striking  illustration  of  this  treatment.  Here 
the  smut  appeared  just  at  the  point  where  the  tassel  was  removed,  and 
of  all  of  the  outbreaks  in  the  plats  60%  were  of  this  nature. 

Of  all  the  experiments  the  most  evident  results  were  obtained  when 
the  plants  were  mutilated  and  then  smut  spores  sprayed  on  those  places. 
When  the  plants  were  young  or  old,  as  in  case  of  mutilation  alone,  but 
little  more  smut  was  produced;  but  when  they  were  about  the  tasseling 
stage,  and  when  ears  were  quite  young,  the  treatment  had  effect.  This 
is  very  prominently  illustrated  in  the  results  in  Table  23,  plats  2-4. 
Here  spores,  in  water  in  two  cases  and  in  manure  water  in  one  case, 
were  sprayed  on  the  young  parts  of  the  tassel  then  fairly  well  protruded, 
without  mutilation,  and  on  most  of  the  young  ears,  after  tearing  open 
the  enveloping  leaves  and  husks  and  so  mutilating  them  and  also  the 
kernels  somewhat.  The  plats  were  first  examined  between  three  and 
four  weeks  later,  and  the  smut  was  then  somewhat  prominent,  showing 
it  had  developed  in  less  than  three  weeks.  Later  final  examinations 
showed  no  unusual  amount  of  smut  in  the  tassels  or  upper  parts  ex- 
posed to  the  spores  without  mutilation,  but  the  outbreaks  in  the  ears 
were  unusually  numerous,  and  chiefly  localized  at  point  of  mutilation. 
The  three  plats  gave  one  hundred  and  three  smutted  ears  out  of  a  total 
of  one  hundred  and  ninety-nine,  or  over  50%.  The  check  plat  gave 
only  one  smutted  ear.  Plate  J  shows  a  photograph  of  the  infected  ears 
from  plat  2  of  this  experiment.  The  sweet  corn  plats  (7-10,  Table  23) 
were  treated  the -same  but  gave  no  results.  Evidently  the  ears  had 
matured  beyond  the  infection  stage  when  the  spores  were  applied.  This 
resistance  due  to  maturity  of  tissues  is  shown  by  the  experiment  in 
1898  (Table  24,  plats  9-11)  where  ears  were  mutilated  late,  (kernels 
changing  from  milk  to  dough  stage)  and  spores  applied,  and  no  success- 
ful infection  took  place. 

It  seems  to  the  writer  that  the  general  failure  to  infect  by  spraying 
spores  on  unmutilated  young  parts  and  on  young  plants  even  when 
mutilated  was  due,  in  part  at  least,  to  the  lack  of  vigorous  germination 
of  spores;  while  with  those  plants  that  were  mutilated  when  abundance 
of  sugar  was  being  carried  into  tassels  and  ears  there  was  formed  a 
more  abundant  and  sweeter  exudation  in  which  the  spores  applied,  or 
the  germs  carried  there  by  the  wind,  multiplied  through  sporidia  to 
such  an  extent  that  infection  was  more  easily  accomplished. 

Relation  to  Land,  etc.  The  difference  in  the  manner  of  infection 
puts  corn  smut  in  a  somewhat  different  relationship  to  such  environ- 
mental conditions  as  are  produced  by  land,  season,  etc.  It  is  difficult 
to  judge  of  the  weight  these  have  in  determining  the  amount  of  smut 


33° 


BULLETIN    NO.     57. 


Average  outbreaks,  etc. 

II 

4 

Kate  of 

m       i-  pi 

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vpoo.]  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  331 

since  the  period  for  which  corn  can  be  infected  extends  over  such  a 
comparatively  long  time,  while,  on  the  other  hand,  the  struggle  between 
the  host  and  parasite  for  supremacy  after  infection  is  reduced  to  a  short 
time.  The  conditions  that  insure  or  prevent  primary  entrance  are  no 
doubt  of  much  greater  importance  than  those  that  favor  or  hinder  the 
development  of  the  fungus  afterward.  It  has  been  shown  that  the 
sporidia  are  the  active  agents  in  this  primary  infection,  that  their  points 
of  entrance  are  the  aerial  parts  of  the  plant  and  that  they  depend  on 
the  wind  as  a  carrying  agent.  Brefeld  claims  that  manure  is  a  hot-bed 
for  production  of  sporidia.  By  such  means  no  doubt  their  number  is 
so  greatly  increased  that  this  offsets  to  a  great  extent  the  disadvantage 
of  aerial  infection.  It  also  explains  why  land  can  not  be  selected  that 
will  be  entirely  free  from  smut,  for,  while  there  might  be  few  if  any 
germs  in  it,  the  wind  may  blow  such  to  the  corn.  It  also  explains,  on 
the  other  hand,  why  more  smut  may  be  expected  in  one  place  than 
another  if  the  conditions  for  multiplication  of  sporidia  are  more  favor- 
able in  one  than  the  other. 

It  was  to  determine,  if  possible,  the  effect  of  such  external  in- 
fluences that  note  was  made  in  each  experiment  of  the  character  of  the 
land  employed,  and  this  was  varied  as  much  as  possible.  An  examina- 
tion of  the  averages  given  in  each  table  (these  determined  by  using 
averages  of  all  the  plats  except  those  influenced  by  treatment)  shows 
that  there  were  but  two  cases  where  there  was  an  unusually  large  amount 
of  smut.  While  both  of  these  occurred  the  same  year,  the  season 
could  hardly  be  held  responsible  since  other  plats  that  year  showed  no 
unusual  amount. 

The  worst  smutted  corn  was  that  from  which  data  are  given  in 
Table  16.  This  was  as  smutty  corn  as  we  have  ever  seen,  averaging 
forty-two  outbreaks  for  every  one  hundred  stalks.  From  a  fifth  of  an 
acre  all  of  the  smut  was  gathered  and  found  to  weigh  191^  Ibs.  or 
nearly  half  a  ton  per  acre.  (See  Plate  K  for  photograph.)  The  land 
had  not  been  in  corn  in  recent  years,  but  had  been  used  as  a  pasture 
for  cattle,  including  the  previous  fall  and  winter  when  corn  stalks  had 
been  fed  to  them  on  the  further  end.  Early  in  the  spring  the  ground 
had  been  broken  and  got  in  as  good  shape  as  possible  for  sod  land  the 
first  year.  Planting  the  corn  was  unavoidably  delayed  until  June  i5th, 
and  this  lateness  of  planting,  etc.,  had  its*effect  on  the  growth  and  yield 
of  the  corn,  though  it  matured  after  a  fashion.  None  of  the  smut  treat- 
ments had  an  especial  effect,  except  in  the  case  with  mutilation.  The 
plats  all  gave  a  large  amount  of  smut,  showing  general  contagion,  and 
.developed  an  unusually  large  number  of  smutty  ears.  From  all  of  the 
data  gathered  there  were  two  things  that  might  have  had  an  influence  in 
producing  this  unusual  amount  of  smut.  First,  the  land  had  been  used 
as  a  pasture  up  to  the  time  it  was  broken  and  so  had  more  or  less  fresh 


332 


BULLETIN    NO.     57. 


[March, 


Average  outbreaks,  etc.,  10 

5 

Rate  of  out- 

breaks per 
100  stalks. 

O^         C^       ^^ 
vN 

M    O    N  OO 

M      M      M 

IO         >0 

In  aerial 

MOQ 

0    0    O    0 

0         O 

roots. 

In  tassels. 

Oi        O        — 

0     M     N      0 

*         N 

In  maturable 

fO        10       ^         ro  O  VO    •**• 

M                                                            M 

M           O 

ears. 

In  leaves. 

O         w        «• 

N   fO  m  O 

O          O 

In  upper 
nodes. 

O         ^"      00         ^"  ^~oo    ^~ 

O^       vo 

In  lower 
nodes. 

O~i       VO        w 
ro                   p^ 

ro  f»   TJ-  10 
M    M    N 

«O              Tf 

Smutty 
outbreaks. 

N        <O        I/J 
°°        H       fO 

N    O    CO  ""> 
IN   ir>  rj-  M 

O         N 

04           M 

%  smutty 
stalks. 

oo      i^    rs 

M  CO    O  CO 

rf         trt 

Smutty 
stalks. 

<^    M    *5 

M    ON  f^  N 
N  m  m  M 

VO           04 
M             M 

Free  stalks. 

f    »  .  2 

00          M         ^ 

wi  t^  ONOO 

r^  m  M  -<3- 
M   ^-  ro  M 

tO            N 

Total  stalks. 

rO        Q\       f% 
N        "^      Is 

CPl             M 

M    TJ-  ro  M 

PO          N 

Rows. 

N       Tf 

Ol    I       1     10 

O  rn  M 

M     M 

OO           O 

M              M 

VO         C\ 

'  a    '    -   '    •    I    '    * 

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hot  water  (i 

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i goo. ]  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  333 

manure  over  it,  a  condition  which  was  favorable  for  the  development 
of  sporidia.  This  alone,  however,  cannot  explain  the  result,  for  the 
rest  of  the  land  which  had  been  planted  on  time  and  so  matured  a  fair 
crop  as  to  growth,  etc.,  was  not  unusually  smutty.  Plat  16  shows  that 
counts  made  in  this  gave  an  average  of  only  thirteen  outbreaks  per  hun- 
dred stalks.  Second,  the  corn  being  planted  late  with  other  unfavora- 
ble conditions  for  development  did  not  produce  a  crop  that  had  the 
resistant  powers  it  would  have  had  otherwise.  In  other  words,  tissues 
•were  not  so  firm,  parts  were  not  so  securely  wrapped  while  young,  etc. 
This  general  weakness  was  shown  by  the  corn  being  more  easily  blown 
down.  These  are  conditions  that  would  favor  the  sporidia,  when  present, 
in  being  carried  down  to  the  susceptible  parts  and  in  being  able  to  infect 
them.  One  can  not  conclude,  however,  that  such  unfavorable  condi- 
tions to  the  corn  as  are  produced  alone  by  late  planting  will  give  a  smutty 
crop,  since  the  next  year  corn  planted  on  the  same  land  and  growing 
even  more  weakly  (Plats  2-3,  Table  22)  gave  an  unusually  small  amount 
of  smut,  and  the  general  result  of  all  the  other  experiments  with  un- 
usually late  plantings  shows  less  smut  than  in  corn  planted  on  time.  In 
this  second  year  on  the  pasture  land,  however,  there  was  lacking  the 
fresh  manure  of  the  first  year,  and  none  of  the  other  late  plantings  were 
on  land  to  which  manure  had  recently  been  applied. 

The  second  badly  smutted  corn  was  that  recorded  in  Table  17,  in 
which  the  smutty  outbreaks  averaged  twenty-six  per  hundred  stalks. 
This  land  was  selected  because  it  had  quite  a  smutty  crop  on  it  the  year 
before  and  it  was  desired  to  see  what  influence  this  would  have  on  the 
next  crop.  The  four  different  treatments  tried  with  the  corn  did  not 
show  any  positive  results.  There  were,  however,  several  things  pecu- 
liar about  the  occurrence  of  the  smut.  In  the  first  place  it  appeared  in 
small  outbreaks  on  all  parts  of  the  plants.  These  were  more  generally 
distributed  than  those  found  in  any  of  the  other  experiments.  The  tas- 
sels and  leaves  which  ordinarily  are  not  subject  to  smutty  outbreaks  con- 
tained an  unusually  large  number.  These  were  often  inconspicuous.  For 
instance  there  were  found  several  stalks  that  had  but  a  small  outbreak 
in  a  single  flower  in  the  top  of  the  tassel.  This  condition  of  affairs 
forced  the  conviction  at  the  time  that  infection  had  been  aerial  and  local 
and  not  through  the  germinating  seeds  as  supposed  when  the  experiments 
were  planned.  Another  peculiarity  was  the  wide  difference  in  number 
of  outbreaks  between  plats  one  and  four,  known  not  to  be  due  to  treat- 
ment and  certainly  not  an  accidental  variation,  as  all  the  rows  in  plat 
one  gave  a  low  number  of  outbreaks,  while  nearly  all  of  those  in  plat 
four  gave  a  high  number.  The  data  obtained  also  showed  that  the  smut 
gradually  increased  from  plat  one  toward  plat  four,  even  showing  this 
increase  in  the  outbreaks  on  leaves  and  panicles.  This  discovery  led  to 
the  supposition  at  first  that  manure  had  been  used  on  or  near  the  worst 


334 


BULLETIN    NO.     57. 


\_March> 


Average  outbreaks,  etc.     7 

I 

Rate  of 

^              tNfS-V           t»        CO 

M  <n  M  o 

outbreaks 

1C  T  "^ 

per  zoo  stalks 

In  aerial 

M           OOO        O        O 

O    0    0    O 

roots. 

In  tassels. 

0           <SOO        M        « 

0    M    O    0 

In  maturable 

„        i/jrN  — 

M     N      M     0 

ears. 

•v<Nfj 

In  leaves. 

0           OOO        0        O 

o  o  o  o 

In  upper 
nodes. 

OOO        0 

o  o  o  o 

In  lower 

rr>           *)•*••*        C\       m 

o  o  o  o 

nodes. 

Smutty 

0            ~  —  ir         M        t^ 

M     CO    M     O 

outbreaks. 

M>fO«<0        M 

o/,  smutty 
stalks. 

t^          ••<?  O  f)        t^       f~- 
WVf 

M  m  M   o 

Smutty 

^         rso-v      o     o 

M     CO   M     O 

stalks. 

"TtNfO        M 

Free  stalks. 

^     -55    j    £ 

u~i  ft   m  f^ 

Total  stalks. 

01  '          OOlNOO         ^       °° 

IH  a\  o^oo 

H 

Rows. 

1 

oo   O^  O   M 

u-1 

Field  corn. 

Sweet 

corn. 

60   i              .          a>      .   4J      . 

n  x         •       i,     .  u,     . 

S  *           -        3  •  •  3      . 

ox      ,•       c  ~  a    • 

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rt   rt   rt  J^ 
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Plat. 

w    N                  PO    ^*  IO        O 
* 

c^oo  o>  o 

1900.]  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  335 

infected  side,  but  investigation  showed  that  such  was  probably  not  the 
case.  It  was  found,  however,  that  this  corn  and  plats  on  either  side  of 
it  had  also  been  used  as  experiment  in  corn  culture,  in  which  part  of 
the  corn  was  plowed  shallow  and  deep  once  a  week,  and  the  rest  the 
same  but  twice  a  week.  This  may  possibly  explain  why  the  plats  were  so 
unevenly  smutted.  In  this  case  then  the  probable  local  causes  were,  first, 
land  that  had  an  unusually  smutty  crop  on  it  the  year  before  and  so 
supposedly  an  unusually  large  number  of  germs  in  the  ground;  and  sec- 
ond, an  unusually  frequent  stirring  of  part  of  the  land. 

Conclusions.  From  the  results  of  the  foregoing  experiments  and 
observations,  the  following  conclusions  are  drawn  relative  to  this  fun- 
gus and  its  host  under  conditions  that  prevail  in  nature,  i.  Corn  smut 
is  more  entirely  dependent  upon  its  sporidia  for  infection  than  any  of 
the  other  smuts  of  cereals.  2.  The  spores,  often  germinate  in  water  but 
much  more  easily  in  nutrient  solutions  and  the  sporidia  formed, especially 
on  exposure  to  air,  greatly  increase  in  numbers.  There  is  every  reason  for 
believing  with  Brefeld  that  manure  is  a  prominent  agent  in  nature  for 
their  multiplication.  3.  Infection  takes  place  rarely,  if  at  all,  through 
the  germinating  seed,  and  so  seed  treatment  has  proved  without  effect 
even  in  degree.  4-.  Infection  is  aerial  -and  local  (points  first  discov- 
ered by  Brefeld).  5.  Wind  serves  as  the  carrying  agent  of  the  sporidia 
to  the  plant,  but  rain  and  dew  no  doubt  help  to  bring  them  down  to 
the  points  where  infection  can  take  place.  6.  Because  of  the  above 
conditions  land  can  not  be  selected  that  will  be  entirely  free  from  smut. 
7.  Avoiding  the  use  of  manure,  selecting  land  not  having  a  smutty  crop 
the  year  previous,  and  properly  tending  to  the  crop,  however,  should 
result  in  a  minimum  amount  of  smut.  8.  Mutilation  of  the  plants  at 
certain  stages  in  their  growth  tends  to  increase  the  amount  of  smut,  es- 
pecially if  germs  be  abundant  at  the  time  of  mutilation.  9.  Unfavor- 
able conditions  for  the  normal  development  of  the  host  by  leaving  its 
parts  improperly  protected  against  infection  and  resistance  are  favor- 
able conditions  for  development  of  smut  if  germs  are  present  insufficient 
numbers.  10.  Observation  indicates  that  different  varieties  of  corn 
vary  in  their  protection  from  or  resistance  to  smut,  though  how  much 
this  amounts  to  has  not  been  determined  by  any  experimental  work. 

GRAIN  SMUT  OF  SORGHUM  AND  BROOM-CORN. 

Cintractia  Sorgki-vulgaris  (Tul. )  Clinton. 

Life  History.  One  of  the  most  prominent  effects  of  this  fungus  on 
its  hosts  is  the  transformation  of  the  parts  that  normally  become  the 
flowers  into  small  smutted  kernels.  An  examination  of  one  of  these  out- 
breaks shows  it  to  consist  of  a  membrane,  that  in  time  becomes  dry  and 
ruptured,  filled  with  a  dusty  mass  of  spores,  except  at  the  center,  where 


336 


BULLETIN    NO.     57. 


Average  outbreaks 

(omitting  those 

due 

to  detasseling),  etc 

IO 

Rate  of  out- 
breaks per 
100  stalks. 

VD         O 

m 

(N 

rn 
m 

m 

rn 

N 

N           P4           N           M 

M                 M 

In  tassel. 

O         0 

o 

O 

O 

o 

0 

N          O          O          O 

O           « 

Where 
detasseled. 

2    2 

0 
(S 

5 

00 

2 

I 

r^     ^f     IN     o 

«       0 

In  ears. 

M 

In  leaves. 

0          0 

o 

M 

0 

0 

0 

o       o       o       o 

0         0 

In  upper 
nodes. 

M    t           O 

o 

ro 

« 

M 

O 

CO           N           O           O 

M               0 

In  lower 
nodes. 

•f          N 

CO 

M 

rn 

CO 

•*• 

PJ        m      cc        i- 

M          eM 

Smutty 
outbreaks. 

N                HI 

w 

in 

5? 

o 

m 

M 

M              HI             CO             VD 

(>»         M          M           M 

CO           N 

HI 

%  smutty 
stalks. 

m     vo 

m 

m 

£ 

CO 
CM 

rn 

m 

s?    5    ?    E- 

m      vo 

M                M 

Smutty 
stalks. 

0          -f 
M           H) 

N 

o 

rn 
M 

M 

M 

O        o        N        m 

vo        es        M        M 

HI 

Free  stalks. 

N            HI 

vo 
in 

CO 
CO 

M 

CO 

m 

CO 

m 

M 

O*          Is*         N           ••* 
O>       vO         C^        t^ 

M 

a\      T 

rn        O 

Total  stalks. 

CN        m 

CO          CO 

m 
-s.. 

CO 
(M 

M 

CO 

m 

CO 

& 

in       o>      co       co 

N 

vO        vo 

^      r^ 

Rows. 

N         •$• 

1 
M        rn 

vo 

1 
in 

M 
.    1 

M 
1 

rn 

M 

m 

CO 

M 
1 

•<»-      vo       co        o 

CM           N           M           m 

1        1        1        I 

N           •*• 
rn        rn 

1        1 
HI       m 
m       m 

Treatment. 

'•  a    '. 

.    4)           a,           10           _, 

:*  : 

.  J3      . 

;  to  *~  '•  •"  •  -* 

•J  : 

.    eu      . 

<u 

•      :  3  :  a  :  g 

.•£,.a.o       i- 

:  3  ; 

.  rt     . 

rt 

^  ••§  :§  :1  :§ 

:  E  : 

•   0      • 

Ordinary  seed.  No  treatment  
As  in  i,  but  young  parts  sprayed  with  smut  ii 
about  six  inches  high,  June  18  

b 

0) 

rt 

OJ 
u 
3 

a 

rt 

e 

c 

3 

E 

en 

3 
£ 

C 
en 

Ordinary  seed.  No  treatment  

CO 

M 

.   4) 

a 

3 

1—! 

J3~ 

.2f 

en 

G 

u 

a 

X 

a 

4) 

en 

"a. 

3 
§ 

u 

4) 

rt 

a 

n  manure 

o      J3       a       <o 
a,     •£ 

•i         C         «         _ 

u      -2 

1 

S     "a      .£      a) 

en 
9 

O 

a 

en 

'5 

•a 

rt 

u 

a 

in 

0 
in 

3 

.a 
in 

en 

in 
i* 
O 

0, 
en 

•a 

4) 

g 

a 

en 

O 

"3 

3 
in 

en 

Ordinary  seed.  No  treatment  
Ears  when  rather  old  (passing  from 
mutilated,  Aug.  25  
As  in  9  but  also  spores  in  water  spray 
places  
As  in  9  but  also  spores  in  manure  w 
mutilated  places  
Seed  taken  from  smutted  ears  very  clc 

E  s 

Jj    a/   tn 
E   M  C/5 

u        .— 
4) 

B 

CA5 

Plat. 

M    04 

CO 

* 

m 

0 

^ 

CO    O          O           «           (N 

m 

jgoo.~\  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  337 

the  plant  tissues  have  formed  a  hard  columella.  All  or  only  part  of 
a  panicle  may  have  its  flowers  thus  transformed. 

The  spores  are  generally  sub-spherical  and  about  5  8«  in  diameter. 
Seen  in  mass  they  have  a  dark  olive  brown  color.  The  cell  walls  are 
•smooth,  but  frequently  have  a  papillate  appearance,  due  to  condition 
of  protoplasmic  contents.  Germination  takes  place  very  readily  at  any 
time  of  the  year,  its  character  depending  somewhat  on  medium  used. 
In  general  it  consists  in  the  production  of  a  septate  germ-thread  several 
times  the  length  of  the  spore,  with  the  frequent  formation  of  knee-joints 
at  the  septa.  If  in  water  the  pro-mycelium  is  apt  to  form  few  sporidia 
and  more  infection  threads,  but  if  in  nutrient  solution  there  is  produced, 
while  it  lasts,  an  abundance  of  sporidia. 

Infection  takes  place  by  the  penetration  of  the  infection  threads 
of  the  spores  or  sporidia  into  the  very  young  tissues  of  the  germinat- 
ing seed,  danger  from  this  being  over  by  the  time  the  plants  appear 
above  ground.  The  mycelium  formed  from  the  infection  threads  de- 
velops toward  the  growing  point  of  the  plant,  and  if  successful  in  reach- 
ing this  follows  its  upward  growth,  developing  most  abundantly  in  the 
pith  cells  between  the  bundles.  In  this  way  the  fungus  makes  a  growth 
through  the  eight  to  ten  feet'of  stalk  without  even  showing  its  presence. 
With  the  formation  of  the  flowering  parts,  however,  tne  fungus  threads 
encroach  more  severely  on  the  very  young  plant  cells  and  form  an 
abundance  of  fertile  threads.  From  these  are  developed  the  spores, 
with  the  result  that  instead  of  the  flowers  appearing  on  the  panicles  their 
place  is  taken  by  the  seed-like  bodies  previously  described.  A  careful 
study  of  the  spores,  their  germination,  and  spore  formation  shows  that 
the  fungus  on  both  broom-corn  and  sorghum  is  the  same. 

Damage.  In  the  investigations  with  broom-corn  (see  bulletin  47) 
it  was  found  that  the  injuries  caused  by  this  smut  were  as  follows:  In- 
ferior brush,  the  irregular  rays  spread  out  on  a  thickened  axis  instead 
of  uniform  ones  starting  from  a  single  point;  the  destruction  of  the 
seed;  the  blackening  of  brush  by  the  spores  settling  on  it  when  handled 
damp.  It  was  also  learned  that  while  ordinarily  fields  did  not  have  a 
very  high  per  cent  of  smut  that  occasionally,  especially  in  certain  sea- 
sons, they  became  quite  smutty,  and  that  as  a  whole  this  was  the  worst 
fungous  pest  of  broom-corn. 

In  the  work  with  sorghum  it  has  been  the  endeavor  to  obtain  a  quite 
exact  knowledge  of  the  action  of  the  fungus  on  this  host.  Sorghum,  like 
broom-corn,  is  not  one  of  our  general  agricultural  plants,  though  it  differs 
from  that  in  being  cultivated  more  widely  over  the  state.  This  being  the 
case  it  has  been  difficult  to  get  an  exact  idea  of  the  occurrence  of  the 
smut.  It  seems,  however,  to  be  much  the  same  with  this  as  with  broom- 
corn;  that  is,  as  a  general  thing  the  smut  is  not  very  abundant  or  is 
entirely  absent,  but  in  some  fields  and  in  certain  seasons  the  amount 


338  BULLETIN  NO.   57.  \_March, 

may  be  considerable.  The  abundance  with  which  it  may  sometimes 
occur  was  shown  in  1897  in  an  examination  of  the  fields  of  the  L.  W. 
Cushman  Syrup  Company  of  Urbana.  An  examination  of  several  of 
their  large  fields  showed  the  following  results: 

No.          Variety.                                          Total  counts.  Smutty.  %  Smutty. 

1  White  amber 1500  480                          32 

2  Orange 1 500  66                            4 

3  Orange 1500  106           7 

4 .'-. 15°°  132  9 

As  the  white  amber  field  was  the  largest  it  can  be  seen  that  in  this 

case  the  damage  must  have  been  considerable  if  the  smut  had  a  very 
injurious  effect  on  its  host. 

EXPERIMENTS. 

Experiments  to  determine  Nature  of  Injury.  It  was  to  determine 
the  exact  effects  of  this  smut  on  sorghum  that  an  extended  series  of  ob- 
servations and  experiments  was  made  during  1897-8,  the  results  of  which 
are  given  in  Table  25.  In  explanation  it  may  be  said  that  the  experi- 
ments were  conducted  with  the  orange  and  white  amber  varieties  of 
sorghum,  the  first  year  the  cane  being  selected  from  this  fields  of  the  L.  W. 
Cushman  Syrup  Co.,  and  the  second  year  from  a  special  plat  grown  on 
the  Experiment  Station  grounds  from  yerv  smutty  seed,  so  as  to  make 
the  number  of  smutty  and  free  canes  as  nearly  equal  as  possible.  Con- 
siderable care  was  used  in  the  collection  of  smutted  and  free  canes  so 
that  any  difference  that  was  shown  between  the  two  lots  would  be  en- 
tirely due  to  the  fungus.  The  canes  were  uniformly  cut  on  the  after- 
noon of  one  day  and  the  measurements  and  weights  taken.  The  next 
morning  they  were  carried  to  a  small  mill,  the  juice  extracted,  measured 
and  samples  taken,  which  were  then  turned  over  to  the  Station  chemist, 
Dr.  Hopkins,  who  made  the  analyses  for  sugar  content  that  afternoon, 
using  the  official  German  method. 

From  the  total  weights  and  measurements  the  following  averages 
are  obtained: 

Average  weight  per  100  orange  free  canes  (panicles  on) 78  Ibs. 

"                  "              "  smutty  canes  (           "         )., 57 

Average  weight  per  100  white  amber  free  canes  (panicles  on) 68*4  " 

"                 "                 "        smutty  canes  (           "         ) 47  " 

Average  weight  per  100  free  orange  panicles   13 

"                  "       smutty  orange  panicles 4  ' 

Average  weight  per  100  free  white  amber  panicles 7  " 

"                  "       smutty  white  amber  panicles 3  " 

Average  length  of  the  orange  free  canes. 8.15  ft. 

"              "           "       smutty  canes 7.72 

Average  length  of  the  white  amber  free  canes 8.64  " 

"                                            smutty  canes 8.19  " 

Average  length  of  the  free  orange  panicles 7.9  in. 

"               "      smutty  orange  panicles 6.4 


IQOO.~\  SMUTS    OF    ILLINOIS'    AGRICULTURAL    PLANTS.  339 

Average  length  of  the  free  white  amber  panicles 9.8          in. 

"       smutty  white  amber  panicles 8.4          " 

Average  quantity  of  juice  per  100  orange  free  canes   16.2        qts. 

"       smutty  canes 10.3          " 

Average  quantity  of  juice  per  roo  white  amber  free  canes 15.4          " 

"  smutty  canes 10.1          " 

An  inspection  of  these  averages  shows  that  the  free  cane  (panicles 
on)  of  both  varieties  was  about  one  and  a  half  times  as  heavy  as  the 
smutty.  The  free  panicles  of  the  orange  were  over  three  times  as  heavy 
as  the  smutty,  while  with  the  white  amber  they  were  over  twice  as  heavy. 
This  was  due  to  the  prevention  of  seed  formation  by  the  smut,  and  as 
the  orange  is  much  more  prolific  in  this  respect  than  the  other  the  dif- 
ference between  its  free  and  smutted  panicles  is  consequently  greater. 
This  destruction  of  seed  is  undesirable,  as  it  is  sometimes  saved  for 
feeding  or  sale  and  has  a  commercial  value  of  about  fifty  cents  a  bushel. 
The  effect  of  the  fungus  is  not  only  shown  in  the  weight  of  the  canes,  but 
also  in  their  length,  as  the  smutty  of  both  varieties  averaged  about  five 
inches  shorter  than  the  free.  The  greatest  proportion  of  this  shortening 
took  place  in  the  panicles,  as  in  both  cases  these  averaged  about  an  inch 
and  a  half  shorter  in  the  smutty  canes;  that  is,  between  a  third  and  a 
fourth  of  the  shortening  occurred  in  the  panicles,  while  they  represented 
only  about  a  tenth  to  a  twelfth  of  the  total  length.  The  smutty  canes 
were  also  apparently  more  slender  than  the  free,  and,  while  no  measure- 
ments were  made  to  determine  this,  the  smaller  ratio  of  their  length  to 
their  weight  as  compared  with  the  free  indicates  that  such  was  the  case. 

The  quantity  of  juice  from  each  variety  was  one  and  a  half  times  as 
great  from  the  free  cane  as  from  the  smutty.  This  was  a  very  little 
larger  proportion  in  either  variety  than  the  weight  of  the  free  canes 
(panicles  off )  was  to  the  weight  of  the  smutty  canes.  Here  then  was  an 
injury  that  was  of  considerable  importance,  as  the  juice  is  the  object 
for  which  the  plant  is  raised,  and  we  find  that  the  fungus  has  had  con- 
siderable effect  in  reducing  it.  It  is  also  seen  that  this  loss  is  caused 
chiefly  by  the  reduction  in  the  size  of  the  plants  rather  than  by  a  reduc- 
tion in  the  relative  amount  of  their  juice. 

The  following  table  shows  the  action  of  the  fungus  on  the  total 
sugar  content  of  the  smutty  plants  as  compared  with  the  free  in  the  cases 
where  comparisons  can  be  made: 


White   amber. 

Orange. 

Date.                 Smutty. 

Free. 

Difference. 

Smutty. 

Free. 

Difference. 

Sept.  28  9,  '97.           8.7% 

8.2^& 

0.5* 

95% 

7-5?e 

•2.0% 

" 

8.9 

8.3 

0.6 

10.6 

6.2 

4-4 

1  * 

10.4 

7.2 

3-2 

Oct.   i, 

.... 

10.5 

6.6 

3-9 

" 

ii  5 

6.6 

4.9 

Sept.  7,       '9 

10   I 

95 

o'e  \ 

95 

8.2 

i-3  ) 

14. 

ii.  6 

9.6 

2.0  V  I.I 

10.9 

9.4 

*-5  f 

i.i 

21, 

11.5 

10  8 

0.7  ) 

11.3 

10.9 

0.4  J 

28, 

12.4 

12.2 

0.2  | 

"•5 

ii-3 

O.2  ) 

Oct.    5, 

11.7 

10  8 

09  Vo.7 

10.6 

ii  3 

-0.7  [ 

—0.4 

12,                '                   12-3 

ii-3 

1,0  1 

12.  1 

12.7 

—  .6  1 

34°  BULLETIN   NO.    57.  [March,. 

An  examination  of  this  table  shows  that  the  smutty  cane  gave  a 
higher  per  cent,  of  sugar  in  seventeen  out  of  the  nineteen  analyses  com- 
pared and  in  the  two  cases  where  it  was  higher  in  the  free  the  difference 
was  slight.  It  also  shows  that  the  difference  in  favor  of  the  smutty  cane 
was  quite  variable,  sometimes  being  inconspicuous  and  in  other  cases 
very  marked,  the  average  difference  being  1.4%. 

The  first  analyses  were  of  orange  cane  that  was  hardly  mature 
enough  for  sorghum  making,  and  these  showed  such  strikingly  higher 
percentages  in  favor  of  the  smutted  cane  as  to  arouse  suspicion  as  to 
their  correctness,  and  so  they  were  repeated  a  few  days  later  ,  but  with 
the  same  results.  The  analyses  made  with  white  amber  at  that  time, 
however,  showed  but  small  differences  in  favor  of  the  smutted  cane. 
This  variety  was  then  perhaps  somewhat  beyond  its  prime  for  factory 
use.  This  difference  between  the  two  varieties  was  interpreted  to  be 
due  at  least  in  part  to  the  difference  in  their  maturity,  and  the  fact  that 
the  sample  of  the  orange  cane  selected  in  the  shade  of  some  trees,  and 
so  the  least  mature,  had  the  greatest  difference  in  favor  of  smutted  cane 
gave  some  reason  for  this  belief. 

In  the  second  year's  work  it  was  planned  to  have  anaylses  made  of 
each  variety  at  different  dates  extending  beyond  the  season  of  sorghum 
making  at  both  ends,  to  determine,  if  possible,  whether  maturity  of 
cane  had  anything  to  do  with  this  variation.  While  the  first  analyses 
were  made  much  earlier  than  the  previous  year,  yet  on  account  of  season 
or  earliness  of  planting  the  cane  was  so  far  advanced  that  it  is  doubtful 
if  they  were  made  soon  enough  to  bring  out  the  greatest  difference, 
especially  in  the  orange  variety.  An  inspection  of  the  preceding  table 
shows  that  on  the  whole  there  was  a  general  increase  in  the  per  cent,  of 
sugar  in  both  the  smutty  and  free  cane  from  the  first  to  the  last,  but 
that  as  the  season  advanced  the  difference  between  the  two  diminished. 

In  order  to  have  some  check  on  the  method  of  collection  and  analy- 
sis, duplicate  collections  of  both  smutty  and  free  canes  were  taken  on 
two  occasions,  under  as  nearly  as  possible  the  same  conditions,  to  see  if 
the  sugar  content  between  these  would  be  as  variable  as  between  the 
smutty  and  free  lots.  In  the  first  of  these  collections  (Table  25,  8  with  10 
and  9  with  n)  the  results  ran  very  close  together,  but  in  one  case  in  the 
second  trial  (42  with  43  and  44  with  45)  there  was  a  difference  of  1.2%. 
These  checks  seem  to  indicate  that  the  natural  variation  due  to  collec- 
tion, etc.,  would  not  average  a  half  per  cent.,  not  enough  to  account 
for  the  almost  uniformly  higher  percentages  that  the  smutty  lots  gave. 

We  are  inclined  to  believe  that  this  difference  in  per  cent,  of  sugar 
in  smutty  and  free  cane  is  due  to  the  action  of  the  smut  in  preventing 
seed  formation.  This  operation  is  an  expensive  one  to  the  plant,  and 
apparently  at  the  time,  is  carried  on  at  a  greater  cost  to  the  sugar  con- 
tent than  it  would  require  to  form  smutty  panicles.  If  this  is  true  it 


IQOO.~\  SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  341 

explains  why  the  smutty  panicles  have  a  higher  sugar  content  during 
seed  formation  and  gradually  lose  this  as  the  seed  matures.  It  also 
explains  why  the  orange  variety  gave  such  wide  differences,  at  certain 
periods,  in  favor  of  the  smutted  cane,  since  here  the  production  of  seed 
in  the  free  panicles  is  much  greater  than  with  the  white  amber.  There 
seems  to  be  some  difference  of  opinion,  however,  concerning  effect  of 
seed  production. on  sugar  content,  as  determined  by  comparison  of 
normal  cane  with  that  from  which  the  seeds  or  panicles  had  been 
removed  as  soon  as  appearing.  Professor  Weber,  while  connected  with 
this  University,  made  some  studies  on  this  question  and  claimed  to  have 
found  a  difference  of  4%  in  favor  of  topped  cane.  Later  and  much 
more  extended  experiments  were  carried  on  by  Collier  and  by  Wiley  of 
the  U.  S.  Dept.  of  Agr.  The  sum  total  of  their  analyses  shows  but  little 
difference  between  ordinary  and  topped  cane.  These  analyses  were 
evidently  chiefly  made  during  what  would  be  the  syrup  making  season 
and  so  were  not  usually  early  enough  to  show  the  first  effect  of  topping, 
though  from  data  presented  one  finds  by  grouping  the  earlier  and  the 
later  analyses  together  that  the  former  show  a  difference  in  favor  of 
topped  cane  while  in  the  latter  it  is  very  slight.  The  results  of  these 
analyses,  then,  are  not  contradictory  to  the  belief  that  at  first  the  seed 
is  produced  at  a  cost  of  sugar  content,  though  topping,  as  with  smut 
ting,  may  not  prove  of  final  benefit. 

Conclusions  as  to  Effect  of  Smut  on  Sorghum.  The  action  of  this 
smut  on  its  host,  ias  gleaned  from  the  above  investigations  seems  to  be  as 
follows  :  From  the  time  of  infection  of  the  germinating  seed  to  time  of 
seed  production,  that  is  during  growing  season,  the  smutted  plant  has 
to  furnish  food  to  the  fungus  for  its  growth  and  this,  with  other  undeter- 
mined effects  of  fungus  on  host,  is  done  at  a  cost  to  the  weight  and  size 
of  its  cane.  This  injury  becomes  most  exaggerated  in  the  panicles,  be- 
cause it  is  here  that  the  fungus  becomes  most  vigorous  in  its  develop- 
ment, actually  preventing  the  formation  of  the  seed.  The  production 
of  seed,  however,  is  a  costly  process  for  a  plant,  and  in  this  case  re- 
quires more  food  material  than  it  does  to  form  the  smutted  panicles, 
hence  the  smutted  cane  may  show  a  higher  per  cent,  of  sugar  at  this 
stage  than  the  free.  With  maturity  of  seed,  however,  this  difference 
disappears  so  that  at  the  proper  season  for  sorghum  making  it  is  of  little 
economic  importance.  On  the  other  hand,  however,  the  quantity  of 
juice  in  the  smutted  plant  is  less  than  in  the  free,  being  in  about  the 
same  proportion  as  the  weight  of  the  cane  is  to  that  of  the  free.  This 
ratio  is  maintained  about  the  same  during  the  whole  season.  From  an 
agricultural  standpoint,  then,  the  presence  of  smut  is  of  importance  be- 
cause it  both  destroys  the  seed  and  lessens  the  yield  of  sorghum  that  is 
finally  made. 

Miscellaneous  Experiments.    That  the  smut  on  sorghum  and  broom- 


342 


BULLETIN    NO.     57. 


[March, 


TABLE  25.  EXPERIMENTS  CONDUCTED  TO  DETERMINE  EFFECT  OF  SMUT  UPON  SORGHUM.  1897-8. 

Total 
sugars. 

ro  m  mvo   Ml-       o< 

t^  CM         ON  ro  TJ 

in      o        in      o   in  CM   M  in  in       CM 

ro 
CO 

O    ON  C^  O  vO    O         t^OO  00        OO  CO    O         O        vo          « 

M                          M                M                                                                              MM                                     H- 

vO    O  vC    O    ON  ON       CO 

M                M 

%  Invert 
sugars. 

M     M     M     CM     Tl-  CM             t--   ON    -t-           mOM 

ro        H 

ro         MQrorot^O         vN 

CM 

M                1 

CM                                                                     M                                          M              M              t-t 

%  Cane 
sugar. 

CM    -"TO    'I-CO    CM           lOCO  CO           T 

rroro       CM        m       N        m  u->  ONOO  oo   m       O        M 

ON  ON  f~»  O    m  O        vC 

M              M 

t^  C^        00  00  00           O          VO           l- 

M 

Yield  of 
juice,  quarts. 

.   .   .  t   .   . 

>noo       vo  r-x 

^       vO          ^1-       O 

u-ioo  vo         O 

»        CO 

Weight  of 
cane,  panicles 
off,  pounds. 

CM           ro          CM           CM 

O    t»  •<••        ro        O 
CM    CM    CM         ro        ro 

ro       CM  m  T      in  M 

Weight  of 
cane,  panicles 
on,  pounds. 

•  VN    ro          M 

~  m 
ro 

ON       oo         t- 
CM           ro          M 

*           s*?* 

^     >*s 

in 

ro 

CM    ro  CM         ro        ro 

.     -     .  m       c- 

Average 
length,  pani- 
cles off,  feet. 

m       c 

o  r^     oo  vo 

•«  ^-  ON       vO    ON 

ON    M     M               M 

O  t^  ro       m 

•     •     •     •     -vo       0  t^       C^    ; 

t»t-.t-.    fx 

Average 
length,   pani- 
cles on,  feet. 

vo   in  *t"        CM 
t^  moo        O 

Conditions  of  collection. 

:  :  6  :  d  :* 

.     .    TO 

•  OO    * 

O 

s 

ft 

4) 

4) 
'£ 

rt 

M        • 

a    . 
w    • 

...  o 

^ 

E  : 
a  . 

•    4>    2 

u 

rt 

•* 

> 

a 

•  H   •  • 

O 

en      a 
.  <s    .  rt 

Sample  of  juice  taken  from  quantity  at  factory.  .  . 
100  small  smutted  canes,  taken  as  found  in  row.  .  . 
100  small  free  canes  as  near  size  and  place  of  thos 
100  large  smutted  canes  taken  as  found  in  row.  .  . 
100  large  free  canes  as  near  size  and  place  of  those 
100  consecutive  smutted  canes  taken  as  found  in  r 
100  free  canes  from  same  row  as  6,  25  taken  from  < 
and  =;o  from  middle.  . 

50  consecutive  smutty  canes  taken  as  found  in  row 
50  consecutive  free  canes  taken  same  row  and  pla 
50  consecutive  smutty  canes  taken  as  found  in  sai 
8.  but  bevond.  . 

50  consecutive  free  canes  taken  as  found  in  same  pi 
Sample  of  juice  taken  from  quantity  at  factory.  .  . 
50  smutted  canes  taken  as  found  in  row.  Leaves 
frost  . 

50  free  canes  taken  same  row  and  place  as  13.  Lea 
bv  frost.  . 

50  smutted  canes  taken  as  found  from  several  rows 
Leaves  still  CTRRO 

3 

"a, 

JQ 

a 

4) 

Q 

O         f 

U             1- 

||| 

—  Z3  *C 
60  «   *• 

li-i 

4>    S    C 

'i'd! 

«S  t 
fi  9-  % 

i  ^  £ 

o      E 

m      HH 

Imperfect  sampling  juice  of  No.  14  
50  smutted  canes  taken  as  they  came  in  the  row.  . 
50  free  canes  taken  as  they  came  from  same  place 
50  smutted  canes  taken  as  they  came  in  the  row.  . 
50  free  canes  taken  as  they  came  from  same  row 
as  21.  . 

50  free  canes  taken  from  row  in  which  smut  had 
vented  by  hot  water  treatment  

%  of  smut  in 
field  or  row. 

CM    N    CM 

ro  ro  ro 

N    CM 

ro  rf 

rf 
> 

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SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


343 


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344 


BULLETIN    NO.     57. 


[March, 


corn  is  but  one  species  is  proved  by  the  following   cross   infection  ex- 
periments made  in  1898.      The  broom-corn  did  not  give  so  high  a  per 

TABLE  26.     EXPERIMENT  SHOWING  IDENTITY  OF  BROOM-CORN  AND  SORGHUM  SMUT. 


Plat. 

Treatment  given  seed. 

Total 
stalks. 

Smutty. 

% 

smutty. 

i 

2 

Broom-corn  seed  given  hot  water  treatment. 
Same  as   i   but   mixed   with  sorghum   smut 
afterwards  .          

34° 

284 

0 

46 

o 
16 

3 

4 

Sorghum  seed  given  hot  water  treatment.  .  .  . 
Same  as  3  but  mixed  with  broom-corn  smut 
afterwards  

623 

648 

o 
262 

o 
40 

cent,  of  smutted  plants  because  its  seeds  were  protected  by  the  glumes, 
while  those  of  the  sorghum  were  naked,  a  condition  that  would  make 
considerable  difference  in  the  ability  of  the  smut  to  infect  the  germina- 
ting seed. 

In  the  work  with  oats  it  was  shown  that  time  of  planting  may  have 
something  to  do  with  determining  the  per  cent,  of  smut.  Experiments 
of  this  nature  were  also  carried  on  with  broom-corn  during  the  year 
1897.  A  row  each  of  smutty  seed,  one  and  four  years  old,  was  planted 
every  week  during  the  broom-corn  season  and  extending  beyond  it  in 
the  later  plantings.  These  experiments  (Table  27)  show  that  smut  kept 
for  four  years  in  a  dry  warm  room  still  germinated  sufficiently  to  infect 
a  goodly  number  of  plants,  though  its  vitality  as  well  as  that  of  the  seed 
was  greatly  reduced.  It  was  also  shown,  as  with  the  oats,  that  if  the 
season  of  planting  is  extended  beyond  its  natural  limits,  successful  in- 
fection is  greatly  reduced.  For  instance,  plantings  made  during  May 
averaged  38%  smutty  with  the  one  year  old  seed  and  12%  with  that 
four  years  old,  while  those  made  out  of  season,  June  10-28,  averaged 
only  18%  with  the  former  and  2%  with  the  latter  seed.  There  was, 

TABLE  27.     RELATION  OF  TIME  OF  PLANTING  TO  AMOUNT  OF  SMUT  IN  BROOM-CORN. 


,«W 

3 

SH 

52.  3 

CO 

3 

Planted. 

Seed. 

S?  P 

—  e 

Seed. 

W.  o 

If 

5^» 

W)  «— 

.^ 

^ 

w  •— 

!-«3 

• 

May   6.  ... 

4  years  old 

i  year  old. 

325 

107 

33 

"    10.  .  .  . 

75 

10 

13 

286 

83 

29 

17  

72 

15 

21 

242 

M3 

59 

24.... 

155 

15 

10 

232 

77 

33 

140 

9 

7 

1  80 

65 

36 

June  10.  ... 

97 

4 

4 

163 

33 

20 

15  

119 

0 

o 

221. 

33 

15 

21  .  .  . 

M3 

6 

•  4 

263 

63 

24 

28  

132 

o 

o 

214 

26 

12 

likewise,  considerable  variation  in  the  plantings  during  the  normal  sea- 
son. In  both  of  these  cases  the  amount  of  moisture  in  the  soil  seems 
to  have  been  one  of  the  primary  causes  of  this  variation,  as  there  was  9. 


i  goo.  ] 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


345 


difference   in   this  respect  even  during   May,  while  in  June  the  moisture 
was  considerably  reduced. 

It  has  been  claimed  by  some  writers  that  the  action  of  smut  on 
certain  hosts  is  to  hasten  the  time  of  appearance  of  the  smutty  panicles. 
An  effort  was  made  to  determine  if  this  were  true  in  the  case  of  broom- 
corn.  Counts  of  the  smutty  and  free  panicles  were  made  on  a  small 
plat  four  times  during  the  period  of  protrusion,  as  shown  in  Table  28. 
These  counts  did  not  reveal  any  marked  difference  in  their  time  of 
appearance. 

TABLE  28.     TIME  OF  APPEARANCE  OF  SMUTTY  PANICLES  OF  BROOM-CORN. 


Condition. 

Sept   3. 

Sept.  7. 

Sept.  13 

Sept.  23. 

Total  panicles  out  

10 

53 

168 

214 

Smutty  panicles  out  .  .        

i 

8 

20 

26 

Per  cent,  smutty  

IO 

i"5 

12 

12 

Prevention  Experiments.  It  was  shown  in  the  experiments  con- 
ducted in  1895-6  with  grain  smut  of  broom-corn  (see  bulletin  47)  that 
the  fungus  could  be  prevented  by  the  hot  water  treatment.  During 
1897-8  further  experiments  were  conducted,  especially  for  comparing 
the  hot  water  with  different  treatments  that  had  proved  successful  with 
other  plants.  The  results  are  given  in  Table  29. 

TABLE  29.     PREVENTION  EXPERIMENTS  WITH  BROOM-CORN  SMUT.    1897-8. 


Plat. 

Treatment  given  seed. 

Total. 

Smutty. 

% 

smutty. 

1897. 
i 

2 

Check  plat.     Untreated.     Plants  in  shade.  .. 
Hot  water,  135°  F.  for  15  minutes  

426 

1704 

280 
7 

66 

O.4 

3 

4. 

Potassium  sulfid,  x  Ib.  to  12  gals,  water  
Ceres  pulver,  i  Ib.  to  12  gals,  water  

1749 
13^7 

17 
2O 

I  .0 

I    c 

5 

Copper  sulfate,  i  Ib.  to  5  gals,  water  

93° 

o 

o 

6 

Check  plat.     Untreated.     Plants  in  sun  

1458 

696 

48. 

1898. 
i 

Check  plat.     Untreated    

641 

158 

24    6 

2 

3 

Potassium  sulfid,  i  Ib.  to  10  gals,  water  
Ceres  pulver,  i  Ib.  to  10  gals,  water  

80  1 

842 

32 
30 

4- 
3.6 

4 

Copper  sulfate,  i  Ib.  to  10  gals,  water  

741 

81 

ii  . 

5 
6 

Corrosive  sublimate,  i  Ib.  to  50  gals,  water.. 
Formalin,    i  Ib.  to  50  gals,  water  

587 
578 

no 

141 

18.7 
24.4 

7 

Hot  water,  i33°-i27°  F.  for  15  minutes  

870 

144 

16.5 

In  these  treatments  broom-corn  seed  that  had  been  mixed  with 
smut  was  used,  and  in  all  the  cases,  except  the  hot  water,  the  method 
was  to  sprinkle  the  seed  thoroughly  with  the  solution  used,  letting  it 
stand  a  few  days  before  planting.  In  1897  all  of  the  treatments  were 
quite  successful.  The  next  year,  however,  they  were  not  quite  so  satis- 
factory. The  sprinkling  was  not  so  thorough  this  time,  and,  in  the 
cases  of  the  copper  sulfate,  corrosive  sublimate,  and  formalin,  the  solu- 
tions were  evidently  not  used  strong  enough.  The  hot  water  treatment, 


346 


BULLETIN    NO.     57. 


[March, 


too,  was  made  at  a  lower  temperature  than  the  year  before   and  so  was 
less  successful. 

In  1898  the  same  treatments  that  were  used  with  broom-corn  were 
also  tried  with  sorghum.  In  this  case  the  treatments  were  much  more 
efficient.  This  is  readily  explained  by  the  fact  that  this  seed  was  hulled, 
while  the  broom-corn  seed  was  enclosed  by  the  glumes,  which  condi- 
tion served  to  protect  the  smut  germs  from  the  action  of  the  fungicides. 
The  results,  Table  30,  show  that  even  then  the  formalin  solution  at  least 
was  not  strong  enough. 

TABLE  30.     PREVENTION  EXPERIMENTS  WITH  SORGHUM  SMUT.     1898: 


Plat. 

Treatment  given  seed. 

Total 
stalks. 

Smutty 
stalks. 

% 

smutty. 

i 

Check  plat.    Untreated  

1084 

47Q 

44. 

2 

Potassium  sulfid,  i  Ib.  to  10  gals,  water  

OS6 

13 

i   3 

Ceres  pulver,  i  Ib.  to  10  gals,  water  

1167 

8 

Copper  sulfate    i  Ib   to  10  gals,  water  

1272 

IO 

8 

5 
6 

Corrosive  sublimate,  i  Ib.  to  50  gals,  water.  . 
Formalin    i  Ib.  to  50  gals,  water  

1160 
034 

31 

85 

2.6 

g\ 

7 

Hot  water   135°  7°  F     for  10  minutes   . 

177 

2 

i   i 

8 

Hot  water.  132°-!°  F.,  for  10  minutes.    .  .  . 

870 

13" 

15- 

The  necessity  of  treating  sorghum  or  broom-corn  when  using  hot 
water  at  a  temperature  of  i35°F.  for  15  minutes  was  also  shown  by 
some  wholesale  treatments  made  for  the  Cushman  Syrup  Company.  Six 
bushels  were  treated,  a  bushel  at  a  time.  The  first  treatment  was  made 
at  about  i3o°F.  for  10  minutes.  As  the  glumes  were  all  off  the  seed  it 
was  feared  that  a  higher  temperature  might  injure  its  germination. 
Some  germination  tests,  however,  showed  that  this  was  nowhere,  near 
the  danger  point.  The  rest  of  the  seed  was  treated  at  about  I32CF.  for 
ID  minutes.  Even  this  was  too  low,  as  is  shown  (Table  30,  plat  8)  by 
the  presence  of  15%  of  smutty  plants,  a  much  lower  per  cent.,  though, 
than  in, the  check  lot. 

On  the  whole,  hot  water  treatment  of  the  proper  severity  seems  to 
be  the  most  satisfactory  with  the  smut  of  sorghum  and  broom-corn,  and, 
as  there  is  never  much  seed  used  in  planting  these  crops  and  as  the 
treated  seed  is  easily  dried  out,  it  lacks  much  of  the  objection  made 
against  its  use  with  oats.  It  is  very  probable,  however,  that  if  stronger 
solutions  of  formalin  had  been  used  it  would  also  have  proved  very 

efficient. 

HEAD  SMUT  OF  SORGHUM.* 

Cintractia  Reiliana  (Kiihn). 

This  smut  differs  greatly  from  the  more  common  grain  smut  of 
sorghum,  as  it  converts  the  whole  panicle  into  a  large  irregular  mass. 

*This  species  has  also  been  reported  a  few  times  in  this  country  as  occurring 
on  corn,  but  so  far  has  not  been  found  in  this  state  on  that  host.  It  has  been  classified 
with  the  Ustilagos,  but  examination  of  the  method  of  spore  production  shows  it  to 
be  a  Cintractic^. 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS.  347 

At  first  this  is  enveloped  by  a  whitish  membrane  composed  entirely  of 
sterile  fungous  threads.  Within  this  is  a  dark  mass  of  spores  and  the 
harder  plant  tissues,  consisting  chiefly  of  the  rays  of  the  panicle,  that 
have  not  been  destroyed.  Sometimes  the  panicle  is  only  partially  in- 
fected. The  membrane  soon  becomes  dingy  and  the  spore  mass  more 
of  a  brown  black  color.  In  time  the  outbreak  becomes  ruptured  and 
the  spores  disseminated. 

Under  the  microscope  the  spores  also  appear  quite  different  in 
these  two  species.  Those  of  the  head  smut  are  dark  brown,  mostly 
sub-spherical,  often  with  sides  somewhat  flattened  by  pressure,  and 
mostly  10-15^  in  diameter.  Their  outer  wall  is  minutely  papillate, 
though  sometimes  quite  obscurely.  In  the  few  trials  made  the  spores 
failed  to  germinate,  but  Brefeld  says  that  they  germinate  easily, 
producing  a  three  or  four  celled  pro -mycelium  and  an  abundance  of 
sporidia. 

Apparently  from  the  experiments  of  Kellerman,  infection  takes 
place  through  the  germinating  seed,  though  the  per  cent,  of  infection 
he  produced  was  rather  small.  In  1898  field  experiments  were  con- 
ducted here  with  the  view  of  infecting  the  orange  variety  of  sorghum 
with  this  smut.  In  one  case  the  seed  was  mixed  with  an  abundance  of 
spores  and  in  others  these  spores  were  sprayed  in  water  or  manure  water 
on  the  young  parts  of  the  plants  when  about  six  inches  high.  In  none 
of  the  several  hundred  plants  that  matured  was  any  sign  of  the  smut 
found.  It  is  very  likely  that  the  variety  used  may  have  had  something 
to  do  with  the  negative  results,  as  it  was  not  the  same  from  which  the 
smut  was  taken  and  which  it  was  intended  originally  to  use. 

This  smut  was  first  found  in  Egypt  in  1868  and  named  by  Kithn 
after  its  discoverer.  It  has  been  reported  only  once  in  this  state,  having 
been  found  in  a  sorghum  field  in  the  vicinity  of  Breeds,  in  August, 
1897.  It  was  rather  abundant  in  that  field  and  seemed  to  t)e  doing 
considerable  damage.  It  has  been  reported  in  several  other  places  in 
this  country,  and  in  Kansas  has  been  found  not  uncommon  on  corn,  and 
while  not  so  frequent  on  this  host  as  the  common  smut,  it  seems  to  be 
much  more  injurious  when  present. 

GRAIN  SMUT  OF  HUNGARIAN  GRASS. 

Ustilago   Cramer  i,   Koern. 

In  the  spikes  of  the  different  varieties  of  cultivated  millet  (Setaria 
Italica)  there  is  sometimes  found  a  smut  which  infests  the  individual 
flowers.  An  infected  spike  much  resembles  the  smutted  ones  of  the 
related  fox-tail  grass,  though  the  fungus  is  really  quite  distinct  and 
much  less  common.  Generally  only  the  lower  parts  of  the  glumes  are 
destroyed,  the  smut  showing  through  the  thin  covering  membrane  here 
while  the  upper  parts  are  normally  developed.  Sometimes  the  hard 


348  BULLETIN  NO.   57.  [March, 

flowering  glume  and  palet  escape  entirely  and  then  the  smut  is  less  con- 
spicuous. 

The  spores  in  mass  are  dark  brown,  smooth,  varying  from  occasion- 
ally irregular  oblong  or  oval  to  chiefly  sub-spherical  in  shape  and  from 
8-iow  in  diameter,  with  the  irregular  ones  somewhat  longer  and  nar- 
rower. Brefeld  states  that  neither  in  water  nor  in  nutrient  solutions  do 
the  spores  produce  sporidia,  but  instead  form  a  pro-mycelium  that 
becomes  septate  and  branched. 

This  fungus  does  not  seem  to  occur  frequently  in  this  country,  though 
apparently  not  so  uncommon  in  some  parts  of  Europe.  It  has  been 
found  but  once  in  this  state.  This  was  at  Alto  Pass,  Union  County,  in 
August,  1898,  where  it  was  discovered  in  a  recently  mowed  field  of  Ger- 
man millet,  and  apparently  had  not  been  very  abundant  in  the  field. 
So  far  as  found  no  preventive  experiments  have  been  made  against  this 
fungus,  unless  by  Bolley  of  North  Dakota.  He  recommends  the  sprink- 
ling method  with  formalin  (i  Ib.  to  45  or  50  gals,  water)  as  having  been 
successful  with  a  smut  of  millet. 

LEAF  SMUT  OF  TIMOTHY,   REDTOP  AND  BLUE-GRASS. 

Ustilago  striaeformis  (West.)  Niessl. 

Frequently  on  timothy  and  redtop  and  rarely  on  blue-grass,  there 
is  found  in  this  state  in  late  spring  and  early  summer  a  smut  which 
occurs  in  dusty  outbreaks  on  the  leaves  and  sheaths  and  more  rarely  in 
the  inflorescence.  These  dusty  patches  frequently  merge  into  long  rup- 
tures, which,  when  very  abundant,  cause  the  leaves  to  become  badly 
torn  and  shredded.  Such  plants  are  smaller  than  the  healthy  and  often, 
especially  in  case  of  blue-grass,  are  so  inconspicuous  as  to  be  easily 
over-looked.  Frequently  the  attack  is  so  severe  that  the  plants  do 
not  head  out.  . 

The*  spores  in  mass  have  a  black  brown  color,  average  io-i4«  in 
diameter,  and  are  chiefly  elliptical  to  sub-spherical  in  shape,  with  outer 
coat  covered  with  prominent  echinulations.  The  fungus  is  apparently 
perennial  in  those  hosts  that  live  from  year  to  year,  as  its  mycelium  has 
been  found  abundantly  in  the  bulb-like  bases  of  timothy  and  also  in  the 
young  buds  developed  from  these.  This  seems  to  indicate  also  that  in- 
fection takes  place  through  the  germinating  seed.  The  spores  are  ger- 
minated with  difficulty,  and  out  of  many  trials  the  writer  has  been  only 
partially  successful  a  few  times,  and  then  mostly  with  spores  from  red- 
top.  The  germination  shows  that  this  is  not  a  Tilletia,  as  usually  sup- 
posed, but  an  Ustilago.  The  germination  so  far  as  it  proceeded  con- 
sisted in  the  development  of  a  germ  thread  many  times  the  length  of  the 
spore,  occasionally  giving  rise  to  a  branch  and  becoming  septate  and 
empty  at  the  base  after  it  reached  a  certain  development.  No  sporidia 
were  found.  So  far  as  can  be  learned  the  reason  for  considering  it  a 


i  goo.  ] 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


349 


Tilletia  is  based  on  Fischer  de  Waldheim's  observations  on  spore  forma- 
tion [Pringsheim  Jahrbiicker  7:85.  1869].  Niessel  [Hedwiga  15:i. 
1876]  was  first  to  show  identity  of  forms  described  by  Westendorp  and 
Waldheim,  and  as  he  placed  the  species  with  Ustilago  his  nomenclature 
has  been  followed. 

This  fungus  is  a  not  an  uncommon  one  both  in  this  country  and 
Europe  and  has  been  reported  on  a  number  of  different  wild  and  culti- 
vated grasses.  It  sometimes  does  considerable  damage,  although  it  ia 
not  an  easy  matter  to  determine  how  much  this  is.  It  was  found  in  one 
case  year  after  year  in  a  timothy  field  and  as  it  was  quite  common  it 
evidently  did  considerable  harm.  It  seems,  however,  to  be  most  in- 
jurious to  redtop.  In  1898  Mr.  Frank  Kagy,  of  Kinmundy,  complained 
of  its  being  very  injurious  in  his  fields  of  this  crop,  and  a  later  exam- 
ination showed  that  it  was  causing  an  injury  of  fully  30%  to  the  plants. 
Mr.  Kagy  stated  that  it  had  greatly  cut  down  the  yield  of  seed  from  his 
fields,  at  times  down  to  70  cwt.  from  the  normal  300  cwt.  So  far  as. 
determined  there  have  been  no  attempts  made  with  seed  treatment  for 
prevention  of  this  smut,  but  from  what  is  known  of  its  life  history,  such 
would  seem  to  be  a  successful  means  for  controlling  it. 

G.  P.  CLINTON,   M.  S., 

Assistant  Botanist. 


EXPLANATIONS  OF  ILLUSTRATOINS. 

Plate  A.  i.  Hidden  smut  of  oats,  Ustilago  levis.  z.  Free  panicle.  3.  Loose  smut 
of  oats,  Ustilago  Avence. 

Plate  B.  Experiment  in  producing  hidden  smut  in  oats.  1-2.  Plants  from  plat  merely 
having  glumes  removed  from  seed:  i.  free  plants;  2.  smutted  plants;  total 
smutty  panicles  i  per  cent.  3-5.  Plants  from  plat  having  glumes  removed 
and  then  mixed  with  smut  spores:  3.  free  plants;  4.  partially  smutted 
plants;  5.  wholly  smutted  plants;  total  smutty  panicles  71  per  cent.  See 
Tables  3  and  7.  Ustilago  levis. 

Plate  C.     Smutted  panicle  of  oat  grass.      Ustilago  perennans. 

Plate  D.  Smutted  spikes  of  barley  showing  condition  of  the  loose  smut  with  age. 
Ustilago  nuda. 

Plate  E.     Covered  smut  of  barley.      Ustilago  Hordei. 

Plate  F.  1-2.  Loose  smut  of  wheat,  2  showing  condition  of  spikes  after  spores  are 
worn  away.  Ustilago  Tritici.  3.  Free  spikes  of  wheat.  4.  Spikes  of 
wheat  with  stinking  smut,  showing  the  little  change  in  general  appearance- 
caused  by  this  smut.  Tilletia  foetens. 

Plate  G.     Smutty  outbreaks  from  teosinte.      Ustilago  Zece. 

Plate  H.     Corn  stalks  in  field  showing  smutty  outbreaks.      Ustilago  Zece. 

Plate   I.     Pod  corn  partially  destroyed  by  smut.      Ustilago  Zece. 

Plate  J.  Ears  of  corn  locally  infected  with  smut  by  mutilating  when  young  and 
applying  spores.  Ustilago  Zece. 

Plate  K.  191  yz  Ibs.  of  smutty  outbreaks  taken  from  one-fifth  acre  plat.  See  expla- 
nation of  Table  23,  plat  2.  Ustilago  Zece. 

Plate  L.     Smutted  panicle  of  sorghum.      Cintractia  Sorghi-vulgaris. 

Plate  M.     Smutted  flowers  of  broom-corn.      Cintractia  Sorghi-vulgaris. 


35° 


BULLETIN    NO.     57. 


\_March, 


Plate  N.  Effect  of  grain  smut  of  broom-corn  on  panicles,  figure  with  uniform  rays 
showing  free  panicles  while  the  one  with  enlarged'Central  rachis  showing 
smutted  one.  Cintractia  Sorghi-vulgaris. 

Plate  O.     Head  smut  of  sorghum.      Cintractia  Reiliana. 

Plate  P.     Grain  smut  of  Hungarian  grass.      Ustilago  Crameri. 

Plate  Q.  Leaf  smut  of  grasses,  i.  redtop,  2.  timothy,  3.  blue-grass.  Ustilago 
striaeformis . 

Plate  R.  Photo-micrographs  of  spores  of  various  smuts,  magnified  about  400  di- 
ameters, i.  Cintractia  Sorghi-vulgaris  from  sorghum.  2.  Ustilago 
Tritici  from  wheat.  3.  Ustilago  Zece  from  corn.  4.  Ustilago  striae- 
formis from  timothy.  5.  Cintractia  Reiliana  from  sorghum.  6.  Tille- 
tiafoetens  from  wheat. 

Plate  S.  Germination  of  spores  magnified  about  525  diameters:  a.  spores,  b.  pro- 
mycelia,  c.  sporidia,  d.  infection  threads,  e.  detached  pieces  of  mycelia, 
f.  knee  joints,  i.  Germination  of  Ustilago  Avenae  in  ^  %  acetic  acid 
24-48  hours  after  being  placed  in  liquid.  2.  Same  as  i  but  in  distilled 
water.  3.  Germination  of  Ustilago  levis  in  Cohn's  modified  solution  at 
end  of  24  hours.  4.  Same  as  3  but  at  end  of  2-3  days.  5.  Germination 
of  Ustilago  Tritici  in  Cohn's  mod.  sol.  6.  Germination  of  Ustilago 
striaeformis  from  redtop  in  -£$%  acetic  acid  at  end  of  two  days.  7. 
Same  as  6  except  spores  in  Cohn's  mod.  sol. 

Plate  T.  (a-f.  etc.,  same  as  in  plate  S.)  i.  Various  stages  in  germination  of  Usti- 
lago Zece  from  corn  about  3  days  after  being  placed  in  water.  2.  Same 
as  i  except  spores  germinated  in  contact  with  air  and  showing  development 
of  air  sporidia,  2"  being  but  slightly  magnified.  3.  Same  as  i  but  several 
days  after  spores  were  placed  in  •£§%  acetic  acid,  sporidia  forming  infec- 
tion threads.  4.  Germination  of  Tilletia  foetens  several  days  after  being 
placed  on  moist  plaster  of  Paris  slabs,  c'.  showing  conjugating 'sporidia. 

Plate  U.  Mycelium  of  grain  smut  of  broom-corn  as  shown  in  cross-sections  of  in- 
fected tissue,  i  magnified  about  150  diameters  and  2-6  about  500  diameters, 
i.  Part  of  section  through  epicotyl  where  infection  takes  place,  a.  myce- 
lium, b.  epidermis,  d.  central  cylinder.  2.  Infected  cells  of  i  more  highly 
magnified.  3.  Section  through  leaf  near  juncture  with  epicotyl.  4-6.  Myce- 
lium with  haustoria  in  pith  cells  from  various  places  on  plant. 


SMUTS  OF  ILLINOIS'  AGRICULTURAL  PLANTS. 


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BULLETIN    NO.     57. 


[March,  1900. 


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UNIVERSITY  OF  ILLINOIS-URBANA 


